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如何用过滤器过滤HTTP协议和非HTTP协议编码
在编写web时,最苦恼的事情就是乱码了。
一直没怎么考虑过JSP第一句话中
<%@ page language="java" contentType="text/html; charset=GBK" pageEncoding="GBK"%>的ContentType和pageEncoding具体是用做什么的,害自己做了过滤器也老是出现问题。
Google下:
contentType ------------指定的是JSP页最终 Browser(客户端)所见到的网页内容的编码. pageEncoding ------------指定JSP编写时所用的编码如果害怕忘了在每个jsp都加上这样的编码,或者由于不同环境所需的客户端所见编码的不同。加上过滤器来解决
1.HTTP协议下的过滤:
(1.login.jsp )用来模拟输入数据登录
<%@ page language="java" pageEncoding="GBK"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" > <title>HTTP协议和URL编码</title> </head> <body> <p>这里仅仅POST编码测试</p> <form action="main.jsp" method="post"> <label>测试HTTP协议</label> <input type="text" name="infoPost" /> <input type="submit" value=http://www.mamicode.com/"提交"> >(2.main.jsp )用来模拟得到数据
<%@ page language="java" pageEncoding="GBK"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" > <title>获取页面传过来的值</title> </head> <body> 获取通过HTTP协议传送过来的值 <%=request.getParameter("infoPost") %> <hr> 获取通过URL传送过来的值 <%=request.getParameter("infoGet") %> </body> </html>(3.web.xml)配置<!-- 编码过滤器 --> <filter> <filter-name>EncodeFilter</filter-name> <filter-class>demo.filter.EncodeFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>GBK</param-value> </init-param> </filter> <filter-mapping> <filter-name>EncodeFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
(4.EncodeFilter.java)过滤器类package demo.filter; import java.io.IOException; 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.HttpServletResponse; /** 字符编码 */ public class EncodeFilter implements Filter { protected String encoding; protected FilterConfig filterConfig; public EncodeFilter() { this.encoding = null; this.filterConfig = null; } public void destroy() { filterConfig = null; encoding = null; } public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException { /* * 处理通过HTTP协议提交的数据 */ HttpServletRequest hrequest = (HttpServletRequest) request; HttpServletResponse hresponse = (HttpServletResponse) response; // 这里省略前面两段,直接用request..setCharacterEncoding(encoding);效果是一样的,这里为了说明这个是通过HTTP // 协议提交 System.out.println("编码格式" + encoding); hrequest.setCharacterEncoding(encoding); filterChain.doFilter(request, response); } /* * 过滤器初始化 */ public void init(FilterConfig filterConfig) throws ServletException { this.filterConfig = filterConfig; encoding = filterConfig.getInitParameter("encoding"); } }
结果:
post方式参数存放在请求数据包的消息体中。get方式参数存放在请求数据包的请求行的URI字段中,以?开始以param=value&¶me2=value2的形式附加在URI字段之后。而request.setCharacterEncoding(charset); 只对消息体中的数据起作用,对于URI字段中的参数不起作用。
可以继承扩展HttpServletRequestWrapper 增加过滤功能
添加一个MyEncodeFilter类
package demo.filter; import java.io.UnsupportedEncodingException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; public class MyEncodeFilter extends HttpServletRequestWrapper{ private String encoding="GBK"; public MyEncodeFilter(HttpServletRequest request) { super(request); } public MyEncodeFilter(HttpServletRequest request,String encoding) { super(request); this.encoding=encoding; } //新增加一个转码方法 public String encodeName(String en){ try { return new String(en.trim().getBytes("ISO-8859-1"),encoding); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block return en; } } //增强过滤的方法,就是将URI字段中的参数编码(重写) public String getParameter(String name) { //直接调用父类的getParameter方法获取参数的值 String value=http://www.mamicode.com/super.getParameter(name);>
改变后的Filter:
package demo.filter; import java.io.IOException; 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.HttpServletResponse; /** 字符编码 */ public class EncodeFilter implements Filter { protected String encoding; protected FilterConfig filterConfig; public EncodeFilter() { this.encoding = null; this.filterConfig = null; } public void destroy() { filterConfig = null; encoding = null; } public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException { /* * 处理通过HTTP协议提交的数据 */ HttpServletRequest hrequest = (HttpServletRequest) request; // 这里省略前面两段,直接用request..setCharacterEncoding(encoding);效果是一样的,这里为了说明这个是通过HTTP // 协议提交 System.out.println("编码格式" + encoding); hrequest.setCharacterEncoding(encoding); //新增加方法<只要通过url来头中肯定有get> if(hrequest.getMethod().equalsIgnoreCase("get")){ hrequest=new MyEncodeFilter(hrequest,encoding); } // filterChain.doFilter(hrequest, response); } /* * 过滤器初始化 */ public void init(FilterConfig filterConfig) throws ServletException { this.filterConfig = filterConfig; encoding = filterConfig.getInitParameter("encoding"); } }
解决成功!
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