1. 转发和重定向
转发:url不会发生变化 (查询前端固定模板的数据)
@RequestMapping("/hello1")
public String hello1(Model model){
model.addAttribute("msg","Spring01");
return "hello"; //普通返回
}
重定向:url会发生变化 (登录业务时,跳转页面)
@RequestMapping("/hello2")
public String hello2(Model model){
model.addAttribute("msg","Spring02");
return "redirect:/index.jsp";
}
2. 处理前端请求的数据
2.1 普通字符串
@Controller
@RequestMapping("/user")
public class HelloController {
//处理前端请求的数据:普通字符串
@RequestMapping("receive1")
public String receive(String name,String password,Model model){
System.out.println("接收到了name=>"+name+" pwd:"+password);
String str="name:"+name+"pwd:"+password;
model.addAttribute("msg",str);
return "hello";
}
}
点击启动测试:在前端输出用户名和密码
如果输入中文出现乱码,可以在web.xml文件中添加一个乱码过滤器
如在index.jsp页面内创建一个表单
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<form action="/login" method="post">
<p>用户名:
<input type="text" name="username">
</p>
<p>密码:
<input type="password" name="password">
</p>
<input type="submit">
</form>
</body>
</html>
在控制层controller目录下创建LoginController类
package com.zz.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class LoginController {
@RequestMapping("/login")
public String login(String username, String password, Model model){
System.out.println("接收到了name=>"+username+" pwd:"+password);
model.addAttribute("msg",username);
return "hello";
}
}
点击启动测试:输入中文名,提交表单
出现乱码现象:
解决办法:在web.xml中添加一个乱码过滤器
<!--SpringMVC 给我们提供了一个乱码过滤器-->
<filter>
<filter-name>CharacterEncodingFilter</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>CharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
重启测试后,发现不出现乱码现象
有些极端情况下,SpringMVC 给我们提供的乱码过滤器还不能解决乱码问题,这时可以自定义一个过滤器
package com.zz.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 GenericEncodingFilter implements Filter {
public void destroy() {
}
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);
}
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;
}
}
然后,只需要在web.xml中,在此处改为自定义过滤器的目录位置即可!
如果前端表单内的属性名和控制层不一致,如表单中用户名为user, 而控制层是username,测试运行后结果如下:
发现name的值为null,为了解决这个问题,可在控制层方法的参数前增加注解@RequestParam(“user”)
@RequestMapping("/login")
public String login(@RequestParam("user") String username, String password, Model model){
System.out.println("接收到了name=>"+username+" pwd:"+password);
model.addAttribute("msg",username);
return "hello";
}
再次测试结果:
2.2 对象
如果我们接收到了一个对象,只要保证,前端传递参数名和我们对象的属性一致即可!
先创建一个user类:
package com.zz.pojo;
import lombok.Data;
@Data
public class User {
private int id;
private String name;
private String pwd;
}
@RequestMapping("/login2")
public String login(User user, Model model){
model.addAttribute("msg",user.getId());
System.out.println(user.getName());
System.out.println(user.getPwd());
return "hello";
}
再在控制层controller目录下的LoginController类内编写
@RequestMapping("/login2")
public String login(User user, Model model){
model.addAttribute("msg",user.getId());
System.out.println(user.getName());
System.out.println(user.getPwd());
return "hello";
}
启动测试:在页面内显示id,在控制台显示name和pwd