SpringBoot第 4 讲：SpringBoot+Rest+拦截器

    Spring MVC 的拦截器（Interceptor）与 Java Servlet 的过滤器（Filter）类似，它主要用于拦截用户的请求并做相应的处理，通常应用在权限验证、记录请求信息的日志、判断用户是否登录等功能上。 

一、创建Maven项目

参考：SpringBoot第 1 讲：HelloWorld_秦毅翔的专栏-CSDN博客

二、修改pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<!-- SpringBoot支持01、parent:Begin -->
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.2.RELEASE</version>
	</parent>
	<!-- SpringBoot支持01、parent:End -->
 
	<groupId>org.personal.qin.demos</groupId>
	<artifactId>rest_demo</artifactId>
	<version>1.0.0-SNAPSHOT</version>
	<packaging>jar</packaging>
 
	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<!-- java版本 -->
		<java.version>1.8</java.version>
	</properties>
 
	<dependencies>
		<!-- SpringBoot:Begin -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- SpringBoot:End -->
 
		<!-- SpringMVC:Begin -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
		</dependency>
		<!-- SpringMVC:End -->
 
	</dependencies>
 
	<build>
		<finalName>${project.artifactId}</finalName>
		<plugins>
			<!-- 资源文件拷贝插件 -->
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-resources-plugin</artifactId>
				<configuration>
					<encoding>UTF-8</encoding>
				</configuration>
			</plugin>
			<!-- java编译插件 -->
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
					<encoding>UTF-8</encoding>
				</configuration>
			</plugin>
			<!-- SpringBoot支持03、添加SpringBoot的插件支持:Begin -->
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
			<!-- SpringBoot支持03、添加SpringBoot的插件支持:End -->
		</plugins>
	</build>
</project>

三、自定义RestController 3.1、Rest请求方式

Rest有4中常用HttpRequest请求方式，分别与数据库的增、删、改、查相对应 RequestMapping 数据库操作

@PostMapping insert

@DeleteMapping delete

@PutMapping update

@GetMapping select

3.2、@PathVariable注解的使用

@PathVariable注解用于接收请求路径中的占位符

比如：

@PostMapping("/{username}/{password}")
	public String login(@PathVariable String username, @PathVariable String password) {
		...
	}

浏览器发送请求：

http://127.0.0.1:8080/admin/123456 3.3、实例：TestRestController.java

package demo.rest.controller;
 
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
import demo.rest.entity.HttpResult;
 
@RestController
@RequestMapping("rest")
public class TestRestController {
 
	/**
	 * 增
	 * @param id
	 * @return
	 */
	@PostMapping("/{id}")
	public HttpResult testPost(@PathVariable String id) { // @PathVariable接收请求路径中的占位符
		return new HttpResult(200, "添加数据", id);
	}
 
	/**
	 * 删
	 * @param id
	 * @return
	 */
	@DeleteMapping("/{id}")
	public HttpResult testDelete(@PathVariable String id) { // @PathVariable接收请求路径中的占位符
		return new HttpResult(200, "删除数据", id);
	}
 
	/**
	 * 改
	 * @param id
	 * @return
	 */
	@PutMapping("/{id}")
	public HttpResult testPut(@PathVariable String id) { // @PathVariable接收请求路径中的占位符
		return new HttpResult(200, "修改数据", id);
	}
 
	/**
	 * 查
	 * @param id
	 * @return
	 */
	@GetMapping("/{id}")
	public HttpResult testGet(@PathVariable String id) { // @PathVariable接收请求路径中的占位符
		return new HttpResult(200, "查询数据", id);
	}
}

四、自定义拦截器（非必须）

package demo.rest.interceptors;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
 
import demo.rest.utils.Log;
 
/**
 * SpringMVC中的拦截器，可以添加多个拦截器
 */
@Configuration
public class TestInterceptor extends WebMvcConfigurerAdapter {
	@Override
	public void addInterceptors(InterceptorRegistry registry) {
		HandlerInterceptor handlerInterceptor = new HandlerInterceptor() {
 
			/**
			 * 在请求Controller之前被执行
			 */
			@Override
			public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
					throws Exception {
				Log.i(getClass(), "*******preHandle");
//				String name = request.getParameter("name");
//				if("admin".equals(name)) {
//					return true;
//				} else {
//					return false;
//				}
				return true;
			}
 
			/**
			 * 在请求Controller完成之后被执行
			 */
			@Override
			public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
					ModelAndView modelAndView) throws Exception {
				Log.i(getClass(), "*******postHandle");
			}
 
			/**
			 * 在请求完成后被执行（只有当preHandle的返回值为true时被执行）
			 */
			@Override
			public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
					Exception ex) throws Exception {
				Log.i(getClass(), "*******afterCompletion");
			}
		};
 
		registry.addInterceptor(handlerInterceptor); // 添加拦截器
	}
}

五、启动BootApplication

package demo.rest;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@SpringBootApplication
public class RestBootApplication {
 
	public static void main(String[] args) {
		SpringApplication.run(RestBootApplication.class, args);
	}
}