1 package com.blue.app.common;
 2
 3 import java.io.IOException;
 4 import java.util.Iterator;
 5 import java.util.Map;
 6
 7 import javax.servlet.Filter;
 8 import javax.servlet.FilterChain;
 9 import javax.servlet.FilterConfig;
10 import javax.servlet.ServletException;
11 import javax.servlet.ServletRequest;
12 import javax.servlet.ServletResponse;
13 import javax.servlet.http.HttpServletRequest;
14 import javax.servlet.http.HttpServletResponse;
15
16 /**
17  * 字符编码过滤器
18  * @author 爱茹一婉年
19  *
20  */
21 public class CommonFilter implements Filter {
22
23     /** 保存用户指定编码 */
24     protected String encoding = null;
25
26     /**
27      * 初始化过滤器方法，由系统创建Filter时自动调用 把web.xml中用户指定的编码保存在本类的属性中
28      */
29     public void init(FilterConfig filterConfig) throws ServletException {
30         this.encoding = filterConfig.getInitParameter("encoding");
31     }
32
33     /**
34      * 执行过滤功能 将参数信息按指定的编码进行转换
35      * 针对post进行编码处理，get方式略过
36      */
37     @SuppressWarnings("unchecked")
38     public void doFilter(ServletRequest arg0, ServletResponse arg1,
39             FilterChain chain) throws IOException, ServletException {
40
41         HttpServletRequest request = (HttpServletRequest) arg0;
42         HttpServletResponse response = (HttpServletResponse) arg1;
43
44         if ("POST".equals(request.getMethod())) {
45             //参数转换，因为我们已经它肯定是Http协议的请求。
46             request.setCharacterEncoding(this.encoding);
47             response.setCharacterEncoding(this.encoding);
48             response.setContentType("text/html;charset=" + this.encoding);
49             //------------注意这里上下的顺序不能颠倒-------------
50             //以下测试输出用
51             Map parameterMap = request.getParameterMap();
52             if (!parameterMap.isEmpty()) {
53                 Iterator it = parameterMap.keySet().iterator();
54                 String value[] = null;
55                 while (it.hasNext()) {
56                     value = (String[]) parameterMap.get(it.next());
57                     for (int i = 0; i < value.length; i++) {
58                         System.out.println("编码过滤后的值----" + value[i]);
59                         //System.out.println(this.encoding+"转换结果--------"+new String(value[i].getBytes("ISO-8859-1"),this.encoding));
60                     }
61                 }
62             }
63         }
64         chain.doFilter(arg0, arg1);
65     }
66
67     /**
68      * 销毁方法，在系统销毁Filter之前由系统自动调用
69      */
70     public void destroy() {
71         this.encoding = null;
72     }
73
74 } 

 1         <!-- 编码过滤器 -->
 2       <filter>
 3         <filter-name>CommonFilter</filter-name>
 4         <filter-class>com.blue.app.common.CommonFilter</filter-class>
 5         <init-param>
 6             <param-name>encoding</param-name>
 7             <param-value>gbk</param-value>
 8         </init-param>
 9     </filter>
10     <filter-mapping>
11         <filter-name>CommonFilter</filter-name>
12         <url-pattern>/*</url-pattern>
13     </filter-mapping>