7. Spring MVC 乱码问题

2022-01-16 本文已影响0人 Messix_1102

创建测试页面

创建一个form 表单

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <form action="/springmvc_04/encoding/t1" method="post">
        <input type="text" name="name">
        <input type="submit">
    </form>
</body>
</html>

注意：想要直接访问.jsp 页面，页面必须创建者 web 根目录下！

创建参数接收方法

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class EncodingController {
    @PostMapping("/encoding/t1")
    public String test1(String name, Model model){
        model.addAttribute("msg", name);
        return "test";
    }
}

创建测试jsp页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${msg}
</body>
</html>

启动程序，form表单直接输入中文，提交表单，可以看到结果乱码！
问题排查
打开浏览器调试，发现返回结果本身就是乱码

java 后台打印参数

发现java后台接收到的参数就是乱码！

解决方案

确定浏览器编码为UTF-8
检查Tomcat 配置，tomcat 安装目录...apache-tomcat-7.0.82\conf 下找到 server.xml检查编码配置
如果没有 URIEncoding="UTF-8" 则需要手动添加

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

配置SpringMVC为我们提供的编码过滤器，直接在web.xml 中配置即可！

<url-pattern>/</url-pattern> 必须为 /* 否则jsp页面无效！

<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>

如果还不能解决，则更换过滤器！
去掉SpringMVC过滤器
添加自定义过滤器类

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.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

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 {
        HttpServletResponse myResponse = (HttpServletResponse) servletResponse;
        myResponse.setContentType("text/html;charset=UTF-8");

        // 转换类型为协议相关对象
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        // 对request包装增强
        HttpServletRequest myRequest = new MyRequest(httpServletRequest);
        filterChain.doFilter(myRequest, servletResponse);
    }

    @Override
    public void destroy() {

    }
}

// 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，一边对其进行装饰
    public MyRequest(HttpServletRequest request){
        super(request); // super 必须写
        this.request = request;
    }

    // 对需要增强的方法进行覆盖
    @Override
    public Map getParameterMap(){
        // 获取请求方式
        String method = request.getMethod();
        // post 请求
        if(method.equalsIgnoreCase("post")){
            //处理post乱码
            try{
              request.setCharacterEncoding("utf-8");
              return request.getParameterMap();
            } catch (UnsupportedEncodingException e){
                e.printStackTrace();
            }
        // get 请求
        } else if(method.equalsIgnoreCase("get")){
            Map<String, String[]> parameterMap = request.getParameterMap();
            if(!hasEncode){
                for (String parameterName : parameterMap.keySet()){
                    String[] values = parameterMap.get(parameterName);
                    if (values != null){
                        for (int i = 0; i < values.length; i ++){
                            // 处理get 乱码
                            try {
                                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
    }

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

web.xml 配置自定义过滤器

<filter>
    <filter-name>encoding</filter-name>
    <filter-class>com.hunter.filter.EncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

7. Spring MVC 乱码问题

创建测试页面

解决方案

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