SpringMVC 學習筆記08：解決Get和Post請求的亂碼問題

阿新 • • 發佈：2020-12-31

一、發現問題

1、我們可以在首頁index.jsp編寫一個提交的表單（post請求）

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2020/12/28
  Time: 10:12
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" 
 %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
    <form action="/Springmvc_04_controller_war_exploded/e/t" method="post">
      <input type="text" name="name">
      <input type="submit" 
>
    </form>
  </body>
</html>

2、後臺編寫對應的處理類

package controller;

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

@Controller
public class Encoding {
    @RequestMapping("/e/t" 
)
    public String test(Model model, String name){
        model.addAttribute("msg",name); //獲取表單提交的值
        return "test"; //跳轉到test頁面顯示輸入的值
    }
}

3.編寫test.jsp

<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2020/12/28
  Time: 11:47
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
   ${msg}
</body>
</html>

4.執行Tomcat
在這裡插入圖片描述
輸入123，提交表單：

位址列變為：http://localhost:8080/Springmvc_04_controller_war_exploded/e/t

輸出（test.jsp介面）：
在這裡插入圖片描述
但是如果輸入漢子：

提交表單，地址變為：http://localhost:8080/Springmvc_04_controller_war_exploded/e/t

輸出：
在這裡插入圖片描述
出現；亂碼問題！

二、解決亂碼問題

方式一：修改web.xml，配置SpringMVC 過濾器

<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>

1.1 Post 請求下測試：

在這裡插入圖片描述

提交後顯示（http://localhost:8080/Springmvc_04_controller_war_exploded/e/t）：
在這裡插入圖片描述
測試成功！

1.2 Get請求下測試：

在這裡插入圖片描述
提交後顯示（http://localhost:8080/Springmvc_04_controller_war_exploded/e/t?name=部落格）：

在這裡插入圖片描述
測試成功！

方式二：修改Tomcat配置檔案

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

方式三：自定義過濾器

package 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;

/**
 * 解決get和post請求 全部亂碼的過濾器
 */
public class GenericEncodingFilter implements Filter {

    @Override
    public void destroy() {
    }

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

        // 轉型為與協議相關物件
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        // 對request包裝增強
        HttpServletRequest myrequest = new MyRequest(httpServletRequest);
        chain.doFilter(myrequest, response);
    }

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

}

//自定義request物件，HttpServletRequest的包裝類
class MyRequest extends HttpServletRequestWrapper {

    private HttpServletRequest request;
    //是否編碼的標記
    private boolean hasEncode;
    //定義一個可以傳入HttpServletRequest物件的建構函式，以便對其進行裝飾
    public MyRequest(HttpServletRequest request) {
        super(request);// super必須寫
        this.request = request;
    }

    // 對需要增強方法 進行覆蓋
    @Override
    public Map getParameterMap() {
        // 先獲得請求方式
        String method = request.getMethod();
        if (method.equalsIgnoreCase("post")) {
            // post請求
            try {
                // 處理post亂碼
                request.setCharacterEncoding("utf-8");
                return request.getParameterMap();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        } else if (method.equalsIgnoreCase("get")) {
            // get請求
            Map<String, String[]> parameterMap = request.getParameterMap();
            if (!hasEncode) { // 確保get手動編碼邏輯只執行一次
                for (String parameterName : parameterMap.keySet()) {
                    String[] values = parameterMap.get(parameterName);
                    if (values != null) {
                        for (int i = 0; i < values.length; i++) {
                            try {
                                // 處理get亂碼
                                values[i] = new String(values[i]
                                        .getBytes("ISO-8859-1"), "utf-8");
                            } catch (UnsupportedEncodingException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
                hasEncode = true;
            }
            return parameterMap;
        }
        return super.getParameterMap();
    }

    //取一個值
    @Override
    public String getParameter(String name) {
        Map<String, String[]> parameterMap = getParameterMap();
        String[] values = parameterMap.get(name);
        if (values == null) {
            return null;
        }
        return values[0]; // 取回引數的第一個值
    }

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

web.xml中配置過濾器：

<filter>
        <filter-name>encoding</filter-name>
        <filter-class>filter.GenericEncodingFilter</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>