Spring RestTemplate整理

公众号_码农致富
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原文链接： blog.csdn.net

一、什么是RestTemplate?


RestTemplate是Spring提供的用于访问Rest服务的客户端，RestTemplate提供了多种便捷访问远程Http服务的方法，能够大大提高客户端的编写效率。 


调用RestTemplate的默认构造函数，RestTemplate对象在底层通过使用java.net包下的实现创建HTTP 请求，可以通过使用ClientHttpRequestFactory指定不同的HTTP请求方式。 

ClientHttpRequestFactory接口主要提供了两种实现方式


一种是SimpleClientHttpRequestFactory，使用J2SE提供的方式（既java.net包提供的方式）创建底层的Http请求连接。

 
一种方式是使用HttpComponentsClientHttpRequestFactory方式，底层使用HttpClient访问远程的Http服务，使用HttpClient可以配置连接池和证书等信息。


通过使用RestTemplate仅仅只需要写几行代码，就可以完成直接使用httpclient很多行代码的事情,具体见：spring.io/blog/2009/0…

二、RestTemplate 构造

RestTemplate有三个构造函数：


1.默认构造函数，默认使用SimpleClientHttpRequestFactory，使用JDK自带的java.net包进行网络传输。


2.public RestTemplate(ClientHttpRequestFactory requestFactory)。传入一个ClientHttpRequestFactory，ClientHttpRequestFactory在Spring中的实现有很多个，如HttpComponentsClientHttpRequestFactory，Netty4ClientHttpRequestFactory等，ClientHttpRequestFactory接口的实现类中存在timeout属性等等

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  1. SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();  
  2. requestFactory.setConnectTimeout(1000);  
  3. requestFactory.setReadTimeout(1000);  
  4.   
  5. RestTemplate restTemplate = new RestTemplate(requestFactory);   
SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
requestFactory.setConnectTimeout(1000);
requestFactory.setReadTimeout(1000);

RestTemplate restTemplate = new RestTemplate(requestFactory);
可以在springboot的某个自定义的configure类中的restTemplate 构造方法上添加

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  1. @Bean  
  2. RestTemplate restTemplate(){  
  3.     SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();  
  4.     requestFactory.setConnectTimeout(1000);  
  5.     requestFactory.setReadTimeout(1000);  
  6.     RestTemplate restTemplate = new RestTemplate(requestFactory);  
  7.     return restTemplate;  
  8. }  
@Bean
RestTemplate restTemplate(){
    SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
    requestFactory.setConnectTimeout(1000);
    requestFactory.setReadTimeout(1000);
    RestTemplate restTemplate = new RestTemplate(requestFactory);
    return restTemplate;
}
将RestTemplate 实例注入spring容器中。
调用时可以通过：

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  1. @Autowired  
  2. private RestTemplate  restTemplate;  
@Autowired
private RestTemplate  restTemplate;

来使用。

3.public RestTemplate(List> messageConverters),使用SpringMvc的应该对HttpMessageConverter很熟悉了，RestTemplate默认会给我们设置好常用的HttpMessageConverter，一般很少使用到这个构造方法。


三、RestTemplate 对HTTP Method的支持




四、RestTemplate 使用实例


4.1、GET请求:


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  1. public <T> T getForObject(String url, Class< T> responseType, Object... urlVariables) throws RestClientException   
  2. public <T> T getForObject(String url, Class<T > responseType, Map<String, ?> urlVariables) throws RestClientException  
  3. public <T> T getForObject(URI url, Class<T > responseType) throws RestClientException   
public <T> T getForObject(String url, Class<T> responseType, Object... urlVariables) throws RestClientException 
public <T> T getForObject(String url, Class<T> responseType, Map<String, ?> urlVariables) throws RestClientException
public <T> T getForObject(URI url, Class<T> responseType) throws RestClientException


使用RestTemplate，对GET请求可以通过如下下面的二种方法实现：


(一)、getForEntity函数


该方法返回ResponseEntity，该对象是Spring对Http请求响应的封装，其中主要存储了HTTP的几个重要元素，比如说HTTP请求码的枚举对象HttpStatus（404，405，500等错误码），它的父类事HttpEntity中还存储着HTTP请求的头信息对象HttpHeaders以及泛型类型的请求体对象。


getForEntity有三种重载的方法：

第一种方式:

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  1. @Override  
  2. public <T> ResponseEntity<T> getForEntity(String url, Class <T> responseType, Map<String,  ?> uriVariables)  
  3.             throws RestClientException {  
  4.   
  5.         RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);  
  6.         ResponseExtractor<ResponseEntity<T> > responseExtractor = responseEntityExtractor(responseType);  
  7.         return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);  
  8.     }  
@Override
public <T> ResponseEntity<T> getForEntity(String url, Class<T> responseType, Map<String, ?> uriVariables)
            throws RestClientException {

        RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
        ResponseExtractor<ResponseEntity<T>> responseExtractor = responseEntityExtractor(responseType);
        return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);
    }

该方法提供了三个参数，url就是请求的地址，responseType返回的数据类型，uriVariables为url中参数绑定。会顺序对应url中占位符定义的数字顺序。

第二种方式:

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  1. @Override  
  2. public <T> ResponseEntity<T> getForEntity(String url, Class <T> responseType, Map<String,  ?> uriVariables)  
  3.             throws RestClientException {  
  4.   
  5.         RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);  
  6.         ResponseExtractor<ResponseEntity<T> > responseExtractor = responseEntityExtractor(responseType);  
  7.         return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);  
  8.     }  
@Override
public <T> ResponseEntity<T> getForEntity(String url, Class<T> responseType, Map<String, ?> uriVariables)
            throws RestClientException {

        RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
        ResponseExtractor<ResponseEntity<T>> responseExtractor = responseEntityExtractor(responseType);
        return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);
    }

url参数和responseType和上面一致，只有第三个参数uriVariables是不同的类型，这里使用了Map<String, ?>类型，所以使用该方法进行参数绑定时需要在占位符中指定Map中参数的key值，我们需要向map中put
一个key为id和name的值来对应{id}和{name}


第三种方式:

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  1. @Override  
  2. public <T> ResponseEntity<T> getForEntity(URI url, Class <T> responseType) throws RestClientException {  
  3.       RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);  
  4.       ResponseExtractor<ResponseEntity<T> > responseExtractor = responseEntityExtractor(responseType);  
  5.       return execute(url, HttpMethod.GET, requestCallback, responseExtractor);  
  6. }  
@Override
public <T> ResponseEntity<T> getForEntity(URI url, Class<T> responseType) throws RestClientException {
      RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
      ResponseExtractor<ResponseEntity<T>> responseExtractor = responseEntityExtractor(responseType);
      return execute(url, HttpMethod.GET, requestCallback, responseExtractor);
}

该方法使用URI对象来替代之前的url和urlVariables参数来指定访问地址和参数来指定访问地址和参数绑定。URI是JDK java.net包下的一个类，它表示一个统一的资源标识符引用.


示例:


Controller类:

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  1. /**  
  2.  * projectName: quna-app  
  3.  * fileName: UserController.java  
  4.  * packageName: com.mongodb.fendo.controller  
  5.  * date: 2018-04-13 13:16  
  6.  * copyright(c) 上海xxxxx有限公司  
  7.  */  
  8. package com.mongodb.fendo.controller;  
  9.   
  10. import com.mongodb.fendo.entity.UserEntity;  
  11. import org.springframework.stereotype.Controller;  
  12. import org.springframework.web.bind.annotation.GetMapping;  
  13. import org.springframework.web.bind.annotation.RequestMapping;  
  14. import org.springframework.web.bind.annotation.RequestParam;  
  15. import org.springframework.web.bind.annotation.ResponseBody;  
  16.   
  17. /**  
  18.  * @version: V1.0  
  19.  * @author: fendo  
  20.  * @className: UserController  
  21.  * @packageName: com.mongodb.fendo.controller  
  22.  * @description: 用户Controller  
  23.  * @data: 2018-04-13 13:16    
  24.  **/  
  25. @Controller  
  26. @RequestMapping(value = "/user")  
  27. public class UserController {  
  28.   
  29.     @GetMapping("getNameById")  
  30.     @ResponseBody  
  31.     public String getNameById(@RequestParam int id, @RequestParam String name){  
  32.         if(1==id && "fendo".equals(name)){  
  33.             return "name="+name+",age="+27;  
  34.         }else {  
  35.             return "name="+name;  
  36.         }  
  37.     }  
  38.     @GetMapping("/getUserById")  
  39.     @ResponseBody  
  40.     public UserEntity getUserEntityById(@RequestParam int id,@RequestParam String name){  
  41.         UserEntity user = new UserEntity();  
  42.   
  43.         if(id == 1 && "fendo".equals(name)){  
  44.             user.setId("1");  
  45.             user.setName("fendo");  
  46.             user.setAge("21");  
  47.         }  
  48.   
  49.         if(id ==2 && "arm".equals(name)){  
  50.             user.setId("2");  
  51.             user.setName("arm");  
  52.             user.setAge("24");  
  53.         }  
  54.   
  55.         return user;  
  56.     }  
  57.   
  58.     @GetMapping("/getUserByname")  
  59.     @ResponseBody  
  60.     public String getUserByname(@RequestParam String name){  
  61.         if("fendo".equals(name)){  
  62.             return "123456798";  
  63.         }else{  
  64.             return "哈哈";  
  65.         }  
  66.     }  
  67.   
  68.   
  69. }    
/**
 * projectName: quna-app
 * fileName: UserController.java
 * packageName: com.mongodb.fendo.controller
 * date: 2018-04-13 13:16
 * copyright(c) 上海xxxxx有限公司
 */
package com.mongodb.fendo.controller;

import com.mongodb.fendo.entity.UserEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * @version: V1.0
 * @author: fendo
 * @className: UserController
 * @packageName: com.mongodb.fendo.controller
 * @description: 用户Controller
 * @data: 2018-04-13 13:16  
 **/
@Controller
@RequestMapping(value = "/user")
public class UserController {

    @GetMapping("getNameById")
    @ResponseBody
    public String getNameById(@RequestParam int id, @RequestParam String name){
        if(1==id && "fendo".equals(name)){
            return "name="+name+",age="+27;
        }else {
            return "name="+name;
        }
    }
    @GetMapping("/getUserById")
    @ResponseBody
    public UserEntity getUserEntityById(@RequestParam int id,@RequestParam String name){
        UserEntity user = new UserEntity();

        if(id == 1 && "fendo".equals(name)){
            user.setId("1");
            user.setName("fendo");
            user.setAge("21");
        }

        if(id ==2 && "arm".equals(name)){
            user.setId("2");
            user.setName("arm");
            user.setAge("24");
        }

        return user;
    }

    @GetMapping("/getUserByname")
    @ResponseBody
    public String getUserByname(@RequestParam String name){
        if("fendo".equals(name)){
            return "123456798";
        }else{
            return "哈哈";
        }
    }


}

测试类:

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  1. package com.mongodb.fendo;  
  2.   
  3. import com.alibaba.fastjson.JSONObject;  
  4. import com.mongodb.fendo.entity.UserEntity;  
  5. import org.junit.Test;  
  6. import org.junit.runner.RunWith;  
  7. import org.springframework.beans.factory.annotation.Autowired;  
  8. import org.springframework.boot.test.context.SpringBootTest;  
  9. import org.springframework.http.HttpEntity;  
  10. import org.springframework.http.HttpHeaders;  
  11. import org.springframework.http.MediaType;  
  12. import org.springframework.test.context.junit4.SpringRunner;  
  13. import org.springframework.web.client.RestTemplate;  
  14. import org.springframework.web.util.UriComponents;  
  15. import org.springframework.web.util.UriComponentsBuilder;  
  16.   
  17. import java.net.URI;  
  18. import java.util.HashMap;  
  19. import java.util.Map;  
  20.   
  21. /**  
  22.  * @version V1.0  
  23.  * @Author fendo  
  24.  * @ClassName RestTemplateTest  
  25.  * @PackageName com.mongodb.fendo  
  26.  * @Description RestTemplate测试类  
  27.  * @Data 2018-04-15 0:07  
  28.  **/  
  29. @RunWith(SpringRunner.class)  
  30. @SpringBootTest  
  31. public class RestTemplateTest {  
  32.   
  33.   
  34.     @Autowired  
  35.     RestTemplate restTemplate;  
  36.   
  37.     @Test  
  38.     public void getNameById(){  
  39.         int id = 2;  
  40.         String name = "qqqqq";  
  41.         String username = restTemplate.getForEntity("http://localhost:8088/user/getNameById? id={1}&name={2}",String.class,new Object[]{id,name}).getBody();  
  42.         System.out.println(username);  
  43.     }  
  44.   
  45.     @Test  
  46.     public void getUserEntityById(){  
  47.         Map<String,Object> params =  new HashMap<>();  
  48.         params.put("id",1);  
  49.         params.put("name","fendo");  
  50.         UserEntity user = restTemplate.getForEntity("http://localhost:8088/user/getUserById? id={id}&name={name}",UserEntity.class,params).getBody();  
  51.         System.out.println(user.toString());  
  52.     }  
  53.   
  54.     @Test  
  55.     public void getUserByname(){  
  56.         String name = "fendo";  
  57.         UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://localhost:8088/user/getUserByname? name={name}").build().expand(name).encode();  
  58.         URI uri = uriComponents.toUri();  
  59.         String response = restTemplate.getForEntity(uri,String.class).getBody();  
  60.         System.out.println(response);  
  61.     }  
  62.   
  63. }  
package com.mongodb.fendo;

import com.alibaba.fastjson.JSONObject;
import com.mongodb.fendo.entity.UserEntity;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;

import java.net.URI;
import java.util.HashMap;
import java.util.Map;

/**
 * @version V1.0
 * @Author fendo
 * @ClassName RestTemplateTest
 * @PackageName com.mongodb.fendo
 * @Description RestTemplate测试类
 * @Data 2018-04-15 0:07
 **/
@RunWith(SpringRunner.class)
@SpringBootTest
public class RestTemplateTest {


    @Autowired
    RestTemplate restTemplate;

    @Test
    public void getNameById(){
        int id = 2;
        String name = "qqqqq";
        String username = restTemplate.getForEntity("http://localhost:8088/user/getNameById?id={1}&name={2}",String.class,new Object[]{id,name}).getBody();
        System.out.println(username);
    }

    @Test
    public void getUserEntityById(){
        Map<String,Object> params = new HashMap<>();
        params.put("id",1);
        params.put("name","fendo");
        UserEntity user = restTemplate.getForEntity("http://localhost:8088/user/getUserById?id={id}&name={name}",UserEntity.class,params).getBody();
        System.out.println(user.toString());
    }

    @Test
    public void getUserByname(){
        String name = "fendo";
        UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://localhost:8088/user/getUserByname?name={name}").build().expand(name).encode();
        URI uri = uriComponents.toUri();
        String response = restTemplate.getForEntity(uri,String.class).getBody();
        System.out.println(response);
    }

}


(二)、getForObject函数


该方法可以理解对getForEntity的进一步封装，它通过HttpMessageConverterExtractor对http的请求响应体body内容进行对象转换，实现请求直接返回包装好的对象内容。

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  1. @Override  
  2. public <T> T getForObject(String url, Class<T > responseType, Object... uriVariables) throws RestClientException {  
  3.         RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);  
  4.         HttpMessageConverterExtractor<T> responseExtractor =  
  5.                 new HttpMessageConverterExtractor< T>(responseType, getMessageConverters(), logger);  
  6.         return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);  
  7. }  
@Override
public <T> T getForObject(String url, Class<T> responseType, Object... uriVariables) throws RestClientException {
        RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
        HttpMessageConverterExtractor<T> responseExtractor =
                new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
        return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);
}

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  1. @Override  
  2. public <T> T getForObject(String url, Class<T > responseType, Map<String, ?> uriVariables) throws RestClientException {  
  3.         RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);  
  4.         HttpMessageConverterExtractor<T> responseExtractor =  
  5.                 new HttpMessageConverterExtractor< T>(responseType, getMessageConverters(), logger);  
  6.         return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);  
  7.     }  
@Override
public <T> T getForObject(String url, Class<T> responseType, Map<String, ?> uriVariables) throws RestClientException {
        RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
        HttpMessageConverterExtractor<T> responseExtractor =
                new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
        return execute(url, HttpMethod.GET, requestCallback, responseExtractor, uriVariables);
    }

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  1. @Override  
  2.     public <T> T getForObject(URI url, Class< T> responseType) throws RestClientException {  
  3.         RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);  
  4.         HttpMessageConverterExtractor<T> responseExtractor =  
  5.                 new HttpMessageConverterExtractor< T>(responseType, getMessageConverters(), logger);  
  6.         return execute(url, HttpMethod.GET, requestCallback, responseExtractor);  
  7. }  
@Override
    public <T> T getForObject(URI url, Class<T> responseType) throws RestClientException {
        RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
        HttpMessageConverterExtractor<T> responseExtractor =
                new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
        return execute(url, HttpMethod.GET, requestCallback, responseExtractor);
}

测试类:

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  1. @Test  
  2. public void Test(){  
  3.     String name = "fendo";  
  4.     String userEntity = restTemplate.getForObject("http://localhost:8088/user/getUserByname? name={name}",String.class,new Object[]{name});  
  5.     System.out.println(userEntity);  
  6.   
  7.     Map<String,Object> params =  new HashMap<>();  
  8.     params.put("id",1);  
  9.     params.put("name",name);  
  10.     UserEntity user = restTemplate.getForObject("http://localhost:8088/user/getUserById? id={id}&name={name}",UserEntity.class,params);  
  11.     System.out.println(user.toString());  
  12.   
  13.     UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://localhost:8088/user/getUserByname? name={name}").build().expand(name).encode();  
  14.     URI uri = uriComponents.toUri();  
  15.     String response = restTemplate.getForObject(uri,String.class);  
  16.     System.out.println(response);  
  17. }  
    @Test
    public void Test(){
        String name = "fendo";
        String userEntity = restTemplate.getForObject("http://localhost:8088/user/getUserByname?name={name}",String.class,new Object[]{name});
        System.out.println(userEntity);

        Map<String,Object> params = new HashMap<>();
        params.put("id",1);
        params.put("name",name);
        UserEntity user = restTemplate.getForObject("http://localhost:8088/user/getUserById?id={id}&name={name}",UserEntity.class,params);
        System.out.println(user.toString());

        UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://localhost:8088/user/getUserByname?name={name}").build().expand(name).encode();
        URI uri = uriComponents.toUri();
        String response = restTemplate.getForObject(uri,String.class);
        System.out.println(response);
    }


4.2、POST请求

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  1. public <T> T postForObject(String url, Object request, Class <T> responseType, Object... uriVariables)  
  2.             throws RestClientException  
  3. public <T> T postForObject(String url, Object request, Class< T> responseType, Map<String, ?> uriVariables)  
  4.             throws RestClientException  
  5. public <T> T postForObject(URI url, Object request, Class< T> responseType) throws RestClientException   
public <T> T postForObject(String url, Object request, Class<T> responseType, Object... uriVariables)
            throws RestClientException
public <T> T postForObject(String url, Object request, Class<T> responseType, Map<String, ?> uriVariables)
            throws RestClientException
public <T> T postForObject(URI url, Object request, Class<T> responseType) throws RestClientException


在RestTemplate中，对post请求时可以通过如下三个方法进行调用实现：


第一种：postForEntity函数


其包含三种重载的方法。第一个重载方法和第二个重载函数的uriVariables参数都用来对url中的参数进行绑定使用，responseType是返回对象的类型定义。增加的request参数，该参数可以是一个普通对象，也可以是一个HttpEntity对象。如果是一个普通对象，而非HttpEntity对象的时候，RestTemplate会将普通对象转换成HttpEntity对象。其中Object中不仅包含了body内容，也包含了header的内容。


[html] view plain copy print?
  1. @Override  
  2. public <T> ResponseEntity<T> postForEntity(String url, Object request, Class <T> responseType, Object... uriVariables)  
  3.             throws RestClientException {  
  4.   
  5.         RequestCallback requestCallback = httpEntityCallback(request, responseType);  
  6.         ResponseExtractor<ResponseEntity<T >> responseExtractor = responseEntityExtractor(responseType);  
  7.         return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);  
  8. }  
@Override
public <T> ResponseEntity<T> postForEntity(String url, Object request, Class<T> responseType, Object... uriVariables)
            throws RestClientException {

        RequestCallback requestCallback = httpEntityCallback(request, responseType);
        ResponseExtractor<ResponseEntity<T>> responseExtractor = responseEntityExtractor(responseType);
        return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);
}

[html] view plain copy print?
  1. @Override  
  2. public <T> ResponseEntity<T> postForEntity(String url, Object request, Class <T> responseType, Map<String,  ?> uriVariables)  
  3.             throws RestClientException {  
  4.   
  5.         RequestCallback requestCallback = httpEntityCallback(request, responseType);  
  6.         ResponseExtractor<ResponseEntity<T >> responseExtractor = responseEntityExtractor(responseType);  
  7.         return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);  
  8. }  
@Override
public <T> ResponseEntity<T> postForEntity(String url, Object request, Class<T> responseType, Map<String, ?> uriVariables)
            throws RestClientException {

        RequestCallback requestCallback = httpEntityCallback(request, responseType);
        ResponseExtractor<ResponseEntity<T>> responseExtractor = responseEntityExtractor(responseType);
        return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);
}

[html] view plain copy print?
  1. @Override  
  2. public <T> ResponseEntity<T> postForEntity(URI url, Object request, Class <T> responseType) throws RestClientException {  
  3.         RequestCallback requestCallback = httpEntityCallback(request, responseType);  
  4.         ResponseExtractor<ResponseEntity<T >> responseExtractor = responseEntityExtractor(responseType);  
  5.         return execute(url, HttpMethod.POST, requestCallback, responseExtractor);  
  6. }  
@Override
public <T> ResponseEntity<T> postForEntity(URI url, Object request, Class<T> responseType) throws RestClientException {
        RequestCallback requestCallback = httpEntityCallback(request, responseType);
        ResponseExtractor<ResponseEntity<T>> responseExtractor = responseEntityExtractor(responseType);
        return execute(url, HttpMethod.POST, requestCallback, responseExtractor);
}

定义接口: [html] view plain copy print ?
  1. @PostMapping("/queryUser1")  
  2. @ResponseBody  
  3. public List<String> queryUser1(@RequestBody UserEntity user){  
  4.     String id = user.getId();  
  5.     if("1".equals(id)){  
  6.         return Arrays.asList("fendo,arm".split(","));  
  7.     }else{  
  8.         return Arrays.asList("admin.sfe".split(","));  
  9.     }  
  10. }  
  11.   
  12. @PostMapping("/queryUser2")  
  13. @ResponseBody  
  14. public String queryUser2(@RequestParam String id,@RequestParam String name){  
  15.     if("1".equals(id)){  
  16.         return "user is " + name;  
  17.     }  
  18.     return "user is not exist";  
  19. }  
    @PostMapping("/queryUser1")
    @ResponseBody
    public List<String> queryUser1(@RequestBody UserEntity user){
        String id = user.getId();
        if("1".equals(id)){
            return Arrays.asList("fendo,arm".split(","));
        }else{
            return Arrays.asList("admin.sfe".split(","));
        }
    }

    @PostMapping("/queryUser2")
    @ResponseBody
    public String queryUser2(@RequestParam String id,@RequestParam String name){
        if("1".equals(id)){
            return "user is " + name;
        }
        return "user is not exist";
    }

测试: [html] view plain copy print ?
  1. @Test  
  2. public void TEST_POST(){  
  3.     UserEntity userEntity = new UserEntity();  
  4.     userEntity.setName("fendo");  
  5.     userEntity.setAddress("北京");  
  6.     userEntity.setAge("23");  
  7.     userEntity.setCreate_date(new Date());  
  8.     userEntity.setEmail("2312892206");  
  9.     userEntity.setSex(1);  
  10.     userEntity.setUser_id("123456789" + Math.random());  
  11.     UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://localhost:8088/user/queryUser1").build();  
  12.     URI uri = uriComponents.toUri();  
  13.     List<String> stringList =  restTemplate.postForEntity(uri,userEntity,List.class).getBody();  
  14.     for (int i = 0; i <  stringList.size(); i++) {  
  15.         System.out.println(stringList);  
  16.     }  
  17.   
  18.   
  19.     HttpHeaders headers = new HttpHeaders();  
  20.     MultiValueMap<String, Object> parammap =  new LinkedMultiValueMap<>();  
  21.     parammap.add("id","1");  
  22.     parammap.add("name","fendo");  
  23.     HttpEntity<Map> entity =  new HttpEntity<>(parammap,headers);  
  24.     String result = restTemplate.postForEntity("http://localhost:8088/user/queryUser2",entity,String.class).getBody();  
  25.     System.out.println(result);  
  26.   
  27. }  
    @Test
    public void TEST_POST(){
        UserEntity userEntity = new UserEntity();
        userEntity.setName("fendo");
        userEntity.setAddress("北京");
        userEntity.setAge("23");
        userEntity.setCreate_date(new Date());
        userEntity.setEmail("2312892206");
        userEntity.setSex(1);
        userEntity.setUser_id("123456789" + Math.random());
        UriComponents uriComponents = UriComponentsBuilder.fromUriString("http://localhost:8088/user/queryUser1").build();
        URI uri = uriComponents.toUri();
        List<String> stringList = restTemplate.postForEntity(uri,userEntity,List.class).getBody();
        for (int i = 0; i < stringList.size(); i++) {
            System.out.println(stringList);
        }


        HttpHeaders headers = new HttpHeaders();
        MultiValueMap<String, Object> parammap = new LinkedMultiValueMap<>();
        parammap.add("id","1");
        parammap.add("name","fendo");
        HttpEntity<Map> entity = new HttpEntity<>(parammap,headers);
        String result = restTemplate.postForEntity("http://localhost:8088/user/queryUser2",entity,String.class).getBody();
        System.out.println(result);

    }


第二种:getForObject函数
该方法可以理解为对getForEntity的进一步封装，它通过org.springframework.web.client.HttpMessageConverterExtractor对HTTP的请求响应体body内容进行对象转换，实现请求直接返回包装好的对象内容。

接口: [html] view plain copy print?
  1. @PostMapping("/getUserEntity")  
  2. @ResponseBody  
  3. public UserEntity getUserEntity(UserEntity userEntity){  
  4.     System.out.println(userEntity.toString());  
  5.     UserEntity user = new UserEntity();  
  6.     user.setId("1");  
  7.     user.setName("fendo");  
  8.     user.setAge("21");  
  9.     return user;  
  10. }  
    @PostMapping("/getUserEntity")
    @ResponseBody
    public UserEntity getUserEntity(UserEntity userEntity){
        System.out.println(userEntity.toString());
        UserEntity user = new UserEntity();
        user.setId("1");
        user.setName("fendo");
        user.setAge("21");
        return user;
    }

测试类: [html] view plain copy print ?
  1. @Test  
  2. public void Test_m(){  
  3.   
  4.     HttpHeaders headers = new HttpHeaders();  
  5.     MultiValueMap<String, Object> parammap =  new LinkedMultiValueMap<>();  
  6.     parammap.add("id", 1);  
  7.     parammap.add("name","fendo");  
  8.     HttpEntity<Map> entity =  new HttpEntity<>(parammap,headers);  
  9.     UserEntity user = restTemplate.postForObject("http://localhost:8088/user/getUserEntity",entity,UserEntity.class);  
  10.     System.out.println(user.toString());  
  11. }  
    @Test
    public void Test_m(){

        HttpHeaders headers = new HttpHeaders();
        MultiValueMap<String, Object> parammap = new LinkedMultiValueMap<>();
        parammap.add("id", 1);
        parammap.add("name","fendo");
        HttpEntity<Map> entity = new HttpEntity<>(parammap,headers);
        UserEntity user = restTemplate.postForObject("http://localhost:8088/user/getUserEntity",entity,UserEntity.class);
        System.out.println(user.toString());
    }

postForObject函数也提供了三个重载的方法

[html] view plain copy print?
  1. @Override  
  2. public <T> T postForObject(String url, Object request, Class< T> responseType, Object... uriVariables)  
  3.             throws RestClientException {  
  4.   
  5.         RequestCallback requestCallback = httpEntityCallback(request, responseType);  
  6.         HttpMessageConverterExtractor<T> responseExtractor =  
  7.                 new HttpMessageConverterExtractor< T>(responseType, getMessageConverters(), logger);  
  8.         return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);  
  9. }  
@Override
public <T> T postForObject(String url, Object request, Class<T> responseType, Object... uriVariables)
            throws RestClientException {

        RequestCallback requestCallback = httpEntityCallback(request, responseType);
        HttpMessageConverterExtractor<T> responseExtractor =
                new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
        return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);
}

[html] view plain copy print?
  1. @Override  
  2. public <T> T postForObject(String url, Object request, Class< T> responseType, Map<String, ?> uriVariables)  
  3.             throws RestClientException {  
  4.   
  5.         RequestCallback requestCallback = httpEntityCallback(request, responseType);  
  6.         HttpMessageConverterExtractor<T> responseExtractor =  
  7.                 new HttpMessageConverterExtractor< T>(responseType, getMessageConverters(), logger);  
  8.         return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);  
  9. }  
@Override
public <T> T postForObject(String url, Object request, Class<T> responseType, Map<String, ?> uriVariables)
            throws RestClientException {

        RequestCallback requestCallback = httpEntityCallback(request, responseType);
        HttpMessageConverterExtractor<T> responseExtractor =
                new HttpMessageConverterExtractor<T>(responseType, getMessageConverters(), logger);
        return execute(url, HttpMethod.POST, requestCallback, responseExtractor, uriVariables);
}

[html] view plain copy print?
  1. @Override  
  2. public <T> T postForObject(URI url, Object request, Class< T> responseType) throws RestClientException {  
  3.         RequestCallback requestCallback = httpEntityCallback(request, responseType);  
  4.         HttpMessageConverterExtractor<T> responseExtractor =  
  5.                 new HttpMessageConverterExtractor< T>(responseType, getMessageConverters());  
  6.         return execute(url, HttpMethod.POST, requestCallback, responseExtractor);  
  7. }  
@Override
public <T> T postForObject(URI url, Object request, Class<T> responseType) throws RestClientException {
        RequestCallback requestCallback = httpEntityCallback(request, responseType);
        HttpMessageConverterExtractor<T> responseExtractor =
                new HttpMessageConverterExtractor<T>(responseType, getMessageConverters());
        return execute(url, HttpMethod.POST, requestCallback, responseExtractor);
}

第三种: 使用postForLocation函数

postForLocation也是提交新资源，提交成功之后，返回新资源的URI，postForLocation的参数和前面两种的参数基本一致，只不过该方法的返回值为Uri，这个只需要服务提供者返回一个Uri即可，该Uri表示新资源的位置。
[html] view plain copy print?
  1. URI uri = restTemplate.postForLocation("http://localhost:8080/xxxx",user);  
  2. System.out.println("uri=="+uri);   
        URI uri = restTemplate.postForLocation("http://localhost:8080/xxxx",user);
        System.out.println("uri=="+uri);

postForLocation函数也提供了三种不同的重载方法 [html] view plain copy print?
  1. @Override  
  2. public URI postForLocation(String url, Object request, Object... uriVariables) throws RestClientException {  
  3.         RequestCallback requestCallback = httpEntityCallback(request);  
  4.         HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables);  
  5.         return headers.getLocation();  
  6. }  
@Override
public URI postForLocation(String url, Object request, Object... uriVariables) throws RestClientException {
        RequestCallback requestCallback = httpEntityCallback(request);
        HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables);
        return headers.getLocation();
}

[html] view plain copy print?
  1. @Override  
  2. public URI postForLocation(String url, Object request, Map<String, ?> uriVariables) throws RestClientException {  
  3.         RequestCallback requestCallback = httpEntityCallback(request);  
  4.         HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables);  
  5.         return headers.getLocation();  
  6. }  
@Override
public URI postForLocation(String url, Object request, Map<String, ?> uriVariables) throws RestClientException {
        RequestCallback requestCallback = httpEntityCallback(request);
        HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor(), uriVariables);
        return headers.getLocation();
}

[html] view plain copy print?
  1. @Override  
  2. public URI postForLocation(URI url, Object request) throws RestClientException {  
  3.         RequestCallback requestCallback = httpEntityCallback(request);  
  4.         HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor());  
  5.         return headers.getLocation();  
  6. }  
@Override
public URI postForLocation(URI url, Object request) throws RestClientException {
        RequestCallback requestCallback = httpEntityCallback(request);
        HttpHeaders headers = execute(url, HttpMethod.POST, requestCallback, headersExtractor());
        return headers.getLocation();
}


postForEntity和postForLocation的区别?

postForEntity返回ResponseEntity，与getForEntity相同 
postForLocation返回URI，返回的是response header中的location信息，一般用于资源定位。


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