当请求来的时候,首先经过拦截器,在经过一系列拦截器处理后,再由再根据URL找到Servlet.执行servlet中的代码.
首先建一个dynamic web project
然后在WebContent或webroot文件夹下面的WEB-INF文件夹下面再建两个文件夹classes和lib.
classes文件夹用来存放加载的字节码文件,lib文件夹用于存放jar包
接下来在WEB-INF目录下新建一个web.xml文件,用于配置拦截器信息和servlet.
然后处理请求页面,可以建一个文件夹专门存放.jsp文件或者.html文件
下面看登录信息字符串解码的程序:
建一个Filter的类,该类实现了Filter接口:
1 package test.filter;
2 import java.io.IOException;
3 import javax.servlet.Filter;
4 import javax.servlet.FilterChain;
5 import javax.servlet.FilterConfig;
6 import javax.servlet.ServletException;
7 import javax.servlet.ServletRequest;
8 import javax.servlet.ServletResponse;
9 public class CharFilter implements Filter {
10 /**
11 * 加载配置的方法
12 */
13 public void init(FilterConfig config) throws ServletException {
14 System.out.println("CharFilter.init()");
15 }
16 /**
17 * 执行拦截的方法
18 */
19 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
20 throws IOException, ServletException {
21 // 将请求到的数据转化为UTF-8 将服务器输入到jsp的汉字进行转码
22 response.setContentType("text/html; charset=utf-8");
23 // 将form表单中的内容提交给服务器时进行解码
24 request.setCharacterEncoding("utf-8");
25 // 将拦截后处理过的内容转发给下一个filter
26 chain.doFilter(request, response);
27 }
28 /**
29 * 销毁拦截器
30 */
31 public void destroy() {
32 }
33 }
下来在进行servlet中处理业务逻辑:
代码如下:
package test.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@WebServlet("/hello")
public class CharServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
protected void service(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String parameter = request.getParameter("username");//获取name参数
String pas = request.getParameter("pas");//获取password参数
System.out.println(parameter+"密码:"+pas);
if("huike".equals(parameter)&&"111".equals(pas)){
request.getRequestDispatcher("/JSP/login.jsp").forward(request, response);
}else{
PrintWriter writer = response.getWriter();
writer.write("账户或密码错误");
writer.close();
}
}
}
登录界面的.jsp文件
<%@ page import="java.util.UUID" %> <!-- 导入UUID的jar包 -->
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>hello world!!你好</h1>
<form action="/Charset/hello" method="POST">
账户:<input type="text" name = "username" placeholder ="hello world" required/><br/><br/>
密码:<input type="password" name = "pas" /><br/><br/>
<input type="submit" />
</form>
</body>
</html>
跳转页面的.jsp文件
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html >
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>login</title>
</head>
<body>
<h1>login</h1>
${name} <!-- 通过servlet中设置的键获取name的值 ,进行参数传递-->
<a>你好</a>
</body>
</html>
web.xml文件
<?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>Charset</display-name>
<filter>
<filter-name>CharFilter</filter-name>
<filter-class>test.filter.CharFilter</filter-class> //filter类的权限定名称
</filter>
<filter-mapping>
<filter-name>CharFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
访问URL:http://localhost:8080/工程名/放.jsp文件的文件夹名/XX.jsp,另:在WEB-INF下面的jsp文件不能直接访问到
时间： 2024-10-04 15:31:57