提交数据与属性名一致时

提交数据：http://localhost:8080//hello?name=11

@RequestMapping("/hello")
    public String test(String name){
        System.out.println(name);
        return "index";
    }

输出: 11

当提交数据与属性名不同时

可通过@RequestParam()解决

提交数据：http://localhost:8080/hello?username=11

@Controller
public class RestFulController {
    @RequestMapping("/hello")
    public String test(@RequestParam("username") String name){
        System.out.println(name);
        return "index";
    }
}

当提交数据是对象时

提交数据：http://localhost:8080/hello?name=1&id=1&age=18

匹配过程：

如果提交的是参数在方法参数列表上，匹配成功，直接使用

如果提交的是对象，则匹配对象里的属性字段，成功则使用，否则报错

@RequestMapping("/hello")
   public String test(User user){
       System.out.println(user);
       return "index";
   }

如果使用对象的话，前端传递的参数名和对象名必须一致，否则就是null。

数据显示

1. 通过ModelAndView ModelAndView 在储存数据的同时，可以进行设置返回的逻辑视图，进行控制展示层的跳转。

public class MyController implements Controller {
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception {
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("msg","mytest");
        modelAndView.setViewName("test");
        return modelAndView;
    }
}

2.通过ModelMap 继承了LinkedHashMap

@RequestMapping("/hello")
public String hello(@RequestParam("username") String name, ModelMap model){
   model.addAttribute("name",name);
   System.out.println(name);
   return "hello";
}

3.通过model 只有几个方法适合用于储存数据，简化了操作

@RequestMapping("/ct2/hello")
public String hello(@RequestParam("username") String name, Model model){
   model.addAttribute("msg",name);
   System.out.println(name);
   return "test";
}

乱码问题

1.添加过滤器

<filter>
   <filter-name>encoding</filter-name>
   <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
   <init-param>
       <param-name>encoding</param-name>
       <param-value>utf-8</param-value>
   </init-param>
</filter>
<filter-mapping>
   <filter-name>encoding</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping>

注：修改xml文件后需要重启服务器

2.修改tomcat配置文件

修改编码为utf-8

<Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1"
          connectionTimeout="20000"
          redirectPort="8443" />

3.自定义过滤器（源自网络）

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;

/**
* 解决get和post请求 全部乱码的过滤器
*/
public class GenericEncodingFilter implements Filter {

   @Override
   public void destroy() {
  }

   @Override
   public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
       //处理response的字符编码
       HttpServletResponse myResponse=(HttpServletResponse) response;
       myResponse.setContentType("text/html;charset=UTF-8");

       // 转型为与协议相关对象
       HttpServletRequest httpServletRequest = (HttpServletRequest) request;
       // 对request包装增强
       HttpServletRequest myrequest = new MyRequest(httpServletRequest);
       chain.doFilter(myrequest, response);
  }

   @Override
   public void init(FilterConfig filterConfig) throws ServletException {
  }

}

//自定义request对象，HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {

   private HttpServletRequest request;
   //是否编码的标记
   private boolean hasEncode;
   //定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰
   public MyRequest(HttpServletRequest request) {
       super(request);// super必须写
       this.request = request;
  }

   // 对需要增强方法 进行覆盖
   @Override
   public Map getParameterMap() {
       // 先获得请求方式
       String method = request.getMethod();
       if (method.equalsIgnoreCase("post")) {
           // post请求
           try {
               // 处理post乱码
               request.setCharacterEncoding("utf-8");
               return request.getParameterMap();
          } catch (UnsupportedEncodingException e) {
               e.printStackTrace();
          }
      } else if (method.equalsIgnoreCase("get")) {
           // get请求
           Map<String, String[]> parameterMap = request.getParameterMap();
           if (!hasEncode) { // 确保get手动编码逻辑只运行一次
               for (String parameterName : parameterMap.keySet()) {
                   String[] values = parameterMap.get(parameterName);
                   if (values != null) {
                       for (int i = 0; i < values.length; i++) {
                           try {
                               // 处理get乱码
                               values[i] = new String(values[i]
                                      .getBytes("ISO-8859-1"), "utf-8");
                          } catch (UnsupportedEncodingException e) {
                               e.printStackTrace();
                          }
                      }
                  }
              }
               hasEncode = true;
          }
           return parameterMap;
      }
       return super.getParameterMap();
  }

   //取一个值
   @Override
   public String getParameter(String name) {
       Map<String, String[]> parameterMap = getParameterMap();
       String[] values = parameterMap.get(name);
       if (values == null) {
           return null;
      }
       return values[0]; // 取回参数的第一个值
  }

   //取所有值
   @Override
   public String[] getParameterValues(String name) {
       Map<String, String[]> parameterMap = getParameterMap();
       String[] values = parameterMap.get(name);
       return values;
  }
}