目标:创建一个简单的呆过滤器的Servlet请求
(1) 过滤器:(假设)客户端发送请求方式与服务器端不一致,客户端(UTF-8),服务器端(ISO-8859-1)
(2) Servlet : 添加一个图书信息,包括图书编号、名称、作者、价格
开始实现:
1. 创建前端页面
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!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" content="text/html; charset=utf-8">
<title>首页</title>
</head>
<body>
<form action="AddServlet" method="post">
<table align="center" border="1" width="350">
<tr>
<td class="2" align="center" colspan="2">
<h2>添加图书信息</h2>
</td>
</tr>
<tr>
<td class="2" align="right">图书编号</td>
<td>
<input type="text" name="id">
</td>
</tr>
<tr>
<td class="2" align="right">图书名称</td>
<td>
<input type="text" name="name">
</td>
</tr>
<tr>
<td class="2" align="right">图书作者</td>
<td>
<input type="text" name="author">
</td>
</tr>
<tr>
<td class="2" align="right">图书价格</td>
<td>
<input type="text" name="price">
</td>
</tr>
<tr>
<td class="2" align="center" colspan="2">
<input type="submit" value="添加">
</td>
</tr>
</table>
</form>>
</body>
</html>
显示界面:
web.xml文件配置信息:
<?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" version="3.0">
<display-name>DynamicProject</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>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>AddServlet</servlet-name>
<servlet-class>com.xxx.servlet.AddServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AddServlet</servlet-name>
<url-pattern>/AddServlet</url-pattern>
</servlet-mapping>
<filter>
<filter-name>CharactorFilter</filter-name>
<filter-class>com.xxx.servlet.CharactorFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CharactorFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
然后编写处理部分Java代码:设计到两个处理函数:
首先看过滤器函数:
package com.xxx.servlet;
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;
public class CharactorFilter implements Filter {
private String encoding = null;
@Override
public void destroy() {
encoding = null;
}
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if (encoding != null) {
request.setCharacterEncoding(encoding);
response.setContentType("text/html;charset=" + encoding);
}
chain.doFilter(request, response);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
encoding = filterConfig.getInitParameter("encoding");
}
}
然后来看响应处理:
package com.xxx.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class AddServlet extends HttpServlet{
/**
*
*/
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException {
PrintWriter out = response.getWriter();
String id = request.getParameter("id");
String name = request.getParameter("name");
String author = request.getParameter("author");
String price = request.getParameter("price");
out.print("<h2>图书信息添加成功<h2>");
out.print("图书编号" + id + "<br>" );
out.print("图书名称" + name + "<br>" );
out.print("图书作者" + author + "<br>" );
out.print("图书价格" + price + "<br>" );
out.flush(); //刷新流
out.close(); //关闭流
}
}
执行一下:
收工。。。。。。。。