20151203--filter

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Strict//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>

<form id="uform" action="saveUser">      

用户代码：<input id="userid" type="text" name="userid" width=30 />
<br><br>
用户名称：<input id="username" type="text" name="username" width=30 />
<br><br>
登录密码：<input id="password" type="password" name="password" width=30 />
<br><br>
确认密码：<input id="passwore" type="password" name="pueren" width=30 />
<br><br>
<input type="submit" value="提交" />
</form>

</body>
</html>

index

package com.hanqi;

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

/**
 * Servlet implementation class saveUser
 */
public class saveUser extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public saveUser() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        
        //获取
        String strUserName = request.getParameter("username");
        
        //转码
        //response.setCharacterEncoding("UTF-8");//输入的是UTF-8
        
        //response.setContentType("text/html;charset=UTF-8");//返回的是UTF-8
        
        //判断
        if(strUserName != null)
        {
            //初始化
            strUserName = new String(strUserName.getBytes("ISO-8859-1"),"UTF-8");
            
            response.getWriter().append("strUserName = " + strUserName);
        }
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

SaveUser

package com.hanqi;

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;

/**
 * Servlet Filter implementation class MyFilter
 */
public class MyFilter implements Filter {

    /**
     * Default constructor. 
     */
    public MyFilter() {
        // TODO Auto-generated constructor stub
    }

    /**
     * @see Filter#destroy()
     */
    public void destroy() {
        // TODO Auto-generated method stub
    }

    /**
     * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        
        String userID = request.getParameter("userid");
        if(userID == null || userID.trim().length() == 0)
        {
            response.getWriter().append("userid  is  error");
        }
        else
        {
            //本句添加在过滤器最下方，用于传递给下一个过滤器或目标页面，构成过滤链条
            chain.doFilter(request, response);
        }
    }

    /**
     * @see Filter#init(FilterConfig)
     */
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}

MyFilter

package com.hanqi;

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;

/**
 * Servlet Filter implementation class Test2
 */
public class Test2 implements Filter {

    /**
     * Default constructor. 
     */
    public Test2() {
        // TODO Auto-generated constructor stub
    }

    /**
     * @see Filter#destroy()
     */
    public void destroy() {
        // TODO Auto-generated method stub
    }

    /**
     * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        
        
        
        response.setCharacterEncoding("UTF-8");//输入的是UTF-8
        
        response.setContentType("text/html;charset=UTF-8");//返回的是UTF-8
                
        
        
        chain.doFilter(request, response);
    }

    /**
     * @see Filter#init(FilterConfig)
     */
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}

Test2

package com.hanqi;

import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRequestAttributeEvent;
import javax.servlet.ServletRequestAttributeListener;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpSessionActivationListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

/**
 * Application Lifecycle Listener implementation class TextListener
 *
 */
public class TextListener implements ServletContextListener, ServletContextAttributeListener, HttpSessionListener, HttpSessionAttributeListener, HttpSessionActivationListener, HttpSessionBindingListener, ServletRequestListener, ServletRequestAttributeListener {

    /**
     * Default constructor. 
     */
    public TextListener() {
        // TODO Auto-generated constructor stub
    }

    /**
     * @see ServletRequestListener#requestDestroyed(ServletRequestEvent)
     */
    public void requestDestroyed(ServletRequestEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionAttributeListener#attributeAdded(HttpSessionBindingEvent)
     */
    public void attributeAdded(HttpSessionBindingEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletContextListener#contextInitialized(ServletContextEvent)
     */
    public void contextInitialized(ServletContextEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionActivationListener#sessionDidActivate(HttpSessionEvent)
     */
    public void sessionDidActivate(HttpSessionEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionBindingListener#valueBound(HttpSessionBindingEvent)
     */
    public void valueBound(HttpSessionBindingEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletContextAttributeListener#attributeAdded(ServletContextAttributeEvent)
     */
    public void attributeAdded(ServletContextAttributeEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletContextAttributeListener#attributeRemoved(ServletContextAttributeEvent)
     */
    public void attributeRemoved(ServletContextAttributeEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionListener#sessionDestroyed(HttpSessionEvent)
     */
    public void sessionDestroyed(HttpSessionEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionAttributeListener#attributeRemoved(HttpSessionBindingEvent)
     */
    public void attributeRemoved(HttpSessionBindingEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletRequestAttributeListener#attributeAdded(ServletRequestAttributeEvent)
     */
    public void attributeAdded(ServletRequestAttributeEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionBindingListener#valueUnbound(HttpSessionBindingEvent)
     */
    public void valueUnbound(HttpSessionBindingEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionActivationListener#sessionWillPassivate(HttpSessionEvent)
     */
    public void sessionWillPassivate(HttpSessionEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionListener#sessionCreated(HttpSessionEvent)
     */
    public void sessionCreated(HttpSessionEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see HttpSessionAttributeListener#attributeReplaced(HttpSessionBindingEvent)
     */
    public void attributeReplaced(HttpSessionBindingEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletContextAttributeListener#attributeReplaced(ServletContextAttributeEvent)
     */
    public void attributeReplaced(ServletContextAttributeEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletRequestAttributeListener#attributeRemoved(ServletRequestAttributeEvent)
     */
    public void attributeRemoved(ServletRequestAttributeEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletContextListener#contextDestroyed(ServletContextEvent)
     */
    public void contextDestroyed(ServletContextEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletRequestAttributeListener#attributeReplaced(ServletRequestAttributeEvent)
     */
    public void attributeReplaced(ServletRequestAttributeEvent arg0)  { 
         // TODO Auto-generated method stub
    }

    /**
     * @see ServletRequestListener#requestInitialized(ServletRequestEvent)
     */
    public void requestInitialized(ServletRequestEvent arg0)  { 
         // TODO Auto-generated method stub
    }
    
}

TextListener

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原文地址：https://www.cnblogs.com/name-hanlin/p/5017605.html