【Java】全站编码过滤器GenericEncodingFilter代码与配置

编码过滤器GenericEncodingFilter：

 package com.fuck.web.filter;

 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.util.Map;

 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletRequestWrapper;

 /**
  * 解决get和post请求 全部乱码
  *
  * @author seawind
  *
  */
 public class GenericEncodingFilter implements Filter {

     @Override
     public void destroy() {
     }

     @Override
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
         // 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);
         response.setContentType("text/html;charset=utf-8");
         chain.doFilter(myrequest, response);
     }

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

 }

 // 自定义request对象
 class MyRequest extends HttpServletRequestWrapper {

     private HttpServletRequest request;

     private boolean hasEncode;

     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();
     }

     @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-INF下的web.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>estoredemo</display-name>
  <filter>
     <filter-name>GenericEncodingFilter</filter-name>
     <filter-class>com.fuck.web.filter.GenericEncodingFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>GenericEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>

=================================================================================================

网上看到另一个，其实和上面基本一模一样，不过也贴上做个备份吧

 import java.io.IOException;
 import java.util.Map;  

 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletRequestWrapper;  

 public class EncodingFilter implements Filter {
     private FilterConfig config = null;
     private String encode = null;  

      public void destroy() {  

     }  

     public void doFilter(ServletRequest request, ServletResponse response,
             FilterChain chain) throws IOException, ServletException {
         response.setContentType("text/html;charset="+encode); //--解决响应乱码
         //--包装改造request中和获取请求参数相关的方法解决请求参数乱码
         chain.doFilter(new MyHttpServletRequest((HttpServletRequest) request), response);
     }  

     public void init(FilterConfig filterConfig) throws ServletException {
         this.config = filterConfig;
         encode = config.getInitParameter("encode") == null?"utf-8":config.getInitParameter("encode");
     }  

     //内部类，装饰类改造HttpServletRequest   的三个方法
     class MyHttpServletRequest extends HttpServletRequestWrapper{
         private HttpServletRequest request = null;
         private boolean isNotEncode = true;
         public MyHttpServletRequest(HttpServletRequest request) {
             super(request);
             this.request = request;
         }  

         @Override
         public Map getParameterMap() {
             try{
                 if(request.getMethod().equalsIgnoreCase("POST")){//--如果是post提交,一行代码解决post提交请求参数乱码
                     request.setCharacterEncoding(encode);
                     return request.getParameterMap();
                 }else if(request.getMethod().equalsIgnoreCase("GET")){//--如果是get提交,则应该手动编解码解决乱码
                     Map<String,String[]> map = request.getParameterMap();//获取有乱码的map
                     if(isNotEncode){//只能在第一次解决乱码
                         for(Map.Entry<String, String[]> entry : map.entrySet()){//遍历map,解决所有值的乱码
                             String [] vs = entry.getValue();
                             for(int i=0;i<vs.length;i++){
                                 vs[i] = new String(vs[i].getBytes("iso8859-1"),encode);
                             }
                         }
                         isNotEncode = false;//设置为false,第二次就不会再进这个代码块了
                     }
                     return map;
                 }else{
                     return request.getParameterMap();
                 }
             }catch (Exception e) {
                 e.printStackTrace();
                 throw new RuntimeException(e);
             }
         }  

         @Override
         public String[] getParameterValues(String name) {
             return (String[]) getParameterMap().get(name);
         }  

         @Override
         public String getParameter(String name) {
             return getParameterValues(name) == null ? null : getParameterValues(name)[0];
         }
     }
 }  

<filter>
    <description>全站乱码过滤器</description>
    <filter-name>encodeFilter</filter-name>
    <filter-class>com.java.filter.EncodingFilter</filter-class>
    <init-param>
        <param-name>encode</param-name>
        <param-value>utf-8</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>encodeFilter</filter-name>
    <url-pattern>/*</url-pattern> -----------------------------------------拦截的路径
</filter-mapping>