JavaWeb——字符編碼過濾器

編寫一個EncodingFilter

1.讀取web.xml文件中配置的當前WEB應用的初始化參數encoding

2.指定請求的字符編碼為1讀取到的編碼

3.調用chain.doFilter()方法"放行"請求

 

   web.xml

 

    <context-param>
        <param-name>encoding</param-name>
        <param-value>UTF-8</param-value>
    </context-param>

 

 

  <filter>
        <filter-name>EncodingFilter</filter-name>
        <filter-class>com.demo.filter.EncodingFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>EncodingFilter</filter-name>
        <url-pattern>/filter/b.jsp</url-pattern>
    </filter-mapping>

 

　　

 

EncodingFilter

 

 

package com.demo.filter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class EncodingFilter extends HttpFilter {

    private String encoding;
    @Override
    protected void init() {
        encoding = getFilterConfig().getServletContext().getInitParameter("encoding");
        System.out.println(encoding);
    }

    @Override
    public void doFilter(HttpServletResponse response, HttpServletRequest request, FilterChain filterChain) throws IOException, ServletException {
        request.setCharacterEncoding(encoding);
        filterChain.doFilter(request,response);
    }
}