jsp中如何使用Filter解决乱码问题呢?

get和post出现的原因

jsp在get和post请求中出现乱码的原因:
    主要是由于没有设置编码内容的方式
	所以才会出现乱码
我们只需加入相应的编码，即可避免此类异常的发生

----------------------------------------------------
实现思路:
    只需编写一个Filter
	 在Filter中对乱码问题进行解决即可

 
EncodingFilter.java

package com.java265.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;

public class EncodingFilter implements Filter {
 
	@Override
	public void init(FilterConfig filterConfig) throws ServletException { 
	}
 
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)throws IOException, ServletException {
		//将ServletRequest强转为HttpServletRequest
		HttpServletRequest httpServletRequest = (HttpServletRequest) request;
		//将ServletResponse强转为HttpServletResponse
		HttpServletResponse httpServletResponse=(HttpServletResponse) response;
		//获取请求方式
		String method = httpServletRequest.getMethod();
		System.out.println("method="+method);
		//设置响应内容的编码方式
		httpServletResponse.setContentType("text/html;charset=utf-8");
		//设置POST请求时HttpServletRequest的编码方式
		httpServletRequest.setCharacterEncoding("utf-8");
		//放行
		chain.doFilter(httpServletRequest, httpServletResponse);
	}
 
	@Override
	public void destroy() { 
	}
}

web.xml:

<?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_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>Filter04</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- 配置编码过滤器 -->
  <filter>
     <filter-name>EncodingFilter</filter-name>
     <filter-class>com.java265.filter.EncodingFilter</filter-class>
  </filter>
  <filter-mapping>
     <filter-name>EncodingFilter</filter-name>
     <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>