處理中文亂碼問題

從後端到前端有時候會出現中文亂碼問題，我們將如何解決：

Java亂碼處理

1.關於配置Tomcat的URIEncoding

修改Tomcat的Server.xml，在Connector標籤中加上URLEncoding參數。

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

2.SpringMVC給我們提供的過濾器

在web.xml中配置過濾器

<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>

3.傳統的通過請求響應設置

response.setCharcacterEncoding("utf-8");
request.setCharcacterEncoding("utf-8");

JSON亂碼問題

1.通過@RequestMaping的produces屬性來實現

//produces:指定響應體返回類型和編碼
@RequestMapping(value = "/json1",produces = "application/json;charset=utf-8")

2.通過Spring配置統一指定，亂碼統一解決

<mvc:annotation-driven>
   <mvc:message-converters register-defaults="true">
       <bean class="org.springframework.http.converter.StringHttpMessageConverter">
           <constructor-arg value="UTF-8"/>
       </bean>
       <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
           <property name="objectMapper">
               <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                   <property name="failOnEmptyBeans" value="false"/>
               </bean>
           </property>
       </bean>
   </mvc:message-converters>
</mvc:annotation-driven>

Html中文亂碼

html源代碼內中文字內容與html編碼不同

網頁的編碼是gbk,而中文的是utf-8;

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

jsp頁面出現亂碼

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

自定義過濾器（強力型）

package com.heng.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的字符編碼
       HttpServletResponse myResponse=(HttpServletResponse) response;
       myResponse.setContentType("text/html;charset=UTF-8");

       // 轉型爲與協議相關對象
       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對象，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對象的構造函數，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手動編碼邏輯只運行一次
               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]; // 取回參數的第一個值
  }

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

然後在web.xml中配置這個過濾器即可！