1.提交的名称和方法的参数名一致
//localhost:8080/user/t1?name=xxx;
@GetMapping("/t1")
public String test1(String name, Model model){
//1.接收前端参数
System.out.println("接收到前端的参数为:" + name);
//2.将返回的结果传递给前端
model.addAttribute("msg", name);
//3.跳转视图
return "test";
}
2.提交的名称和方法的参数名不一致
//加上@RequestParam("username")就知道是从前端接收过来localhost:8080/user/t1?username=xxx;。此时必须要通过username识别
@GetMapping("/t1")
public String test1(@RequestParam("username") String name, Model model){
//1.接收前端参数
System.out.println("接收到前端的参数为:" + name);
//2.将返回的结果传递给前端
model.addAttribute("msg", name);
//3.跳转视图
return "test";
}
3.提交一个对象
//前端接收的是一个对象：id， name， age
//localhost:8080/user/t1?id=1&name=xxx&age=2;
/*
* 1.接收前端用户传递的参数，判断参数的名字，假设名字直接在方法上可以直接使用
* 2.假设传递的是一个对象User，匹配User对象中的字段名：如果名字一致则ok。否则匹配不到
*
* */
@GetMapping("/t2")
public String test2(User user){
System.out.println(user);
//3.跳转视图
return "test";
}
使用对象，前端传递的参数名和对象名必须一致，否则为空。
2.1 ModelAndView
public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("msg","ControllerTest1");
modelAndView.setViewName("test");
return modelAndView;
}
2.2 Model
@RequestMapping("/t2")
public String test(Model model){
model.addAttribute("msg", "ControllerTest2");
return "test";
}
2.3 ModelMap
@GetMapping("/t3")
public String test3(@RequestParam("username") String name,Model map){
map.addAttribute("name",name);
return "test";
}
对比：
1.form表单
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<form action="/encoding/t1" method="post">
<input type="text" name="name">
<input type="submit">
</form>
</body>
</html>
2.写一个controller
@Controller
public class EncodingController {
@PostMapping("/encoding/t1")
public String test(String name, Model model){
model.addAttribute("msg",name);
return "test";
}
}
3.测试结果
前面弄得好好的，结果出了个这
解决办法：
看一下自己Tomcat中的是不是设置的UTF-8。在自己下载路径下-conf-server.xml
<Connector connectionTimeout="20000" port="8080" protocol="HTTP/1.1" redirectPort="8443" URLEncoding="UTF-8"/>
1)修改提交方式
把提交方式post方法改成get方法
2)Spring提供了过滤器，可以在web.xml中直接配置。（这个基本够用）
<!--2.配置 SpringMVC的乱码过滤-->
<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>
3)过滤器解决（这个不行，功能不全）
package com.hxl.filter;
import javax.servlet.*;
import java.io.IOException;
public class EncodingFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("utf-8");
servletResponse.setCharacterEncoding("utf-8");
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
写完就要去注册（web.xml）
<filter>
<filter-name>encoding</filter-name>
<filter-class>com.hxl.filter.EncodingFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>encoding</filter-name>
<url-pattern>/</url-pattern>
</filter-mapping>
4)大神自定义过滤器
package com.hxl.filter;
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 EncodingFilter 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;
}
}
同样需要在web.xml中进行配置
