张志宇 SERVELET JSP学习讲义-HelloWorldServlet_2
接着 我的第一个Servlet程序，为了测试一下浏览器到底是get还是post方法接收信息，修改代码如下：
package com.zzk.cn;
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 HelloWorldServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("dopost...");
//super.doPost(req, resp);
}
/**
*
*/
private static final long serialVersionUID = 1L;//父类或者父类的父类实现了序列化的接口
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("doget....");
PrintWriter out=resp.getWriter();
out.println("<html><head></head><body><center><font color='red'>HelloWorldServlet!</font></center></body></html>");
out.flush();//清理
out.close();//关闭
}
}
写一段html代码：
<form action=http://localhost:8080/my/HelloWorldServlet method=get> <input type=text name=test> <input type=submit value="提交"> </form>
运行tomcat，打开该html文件后，点击提交按钮，会自动进入
<html><head></head><body><center><font color='red'>HelloWorldServlet!</font></center></body></html>的HTML页面
同时，tomcat的DOS窗口会显示doget...一次
但是此时，将html代码替换为dopost方法，如下：
<form action=http://localhost:8080/my/HelloWorldServlet method=post> <input type=text name=test> <input type=submit value="提交"> </form>
通过此html页面打开的新页面无内容，tomcat里显示dopost...一次
我们再来修改servlet代码：
package com.zzk.cn;
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 HelloWorldServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("dopost...");
//super.doPost(req, resp);
doGet(req,resp);
}
/**
*
*/
private static final long serialVersionUID = 1L;//父类或者父类的父类实现了序列化的接口
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("doget....");
PrintWriter out=resp.getWriter();
out.println("<html><head></head><body><center><font color='red'>HelloWorldServlet!</font></center></body></html>");
out.flush();//清理
out.close();//关闭
}
}
这时页面内容显示出来
<html><head></head><body><center><font color='red'>HelloWorldServlet!</font></center></body></html>
tomcat里显示
dopost...
doget....
接下来，重写servlet
package com.zzk.cn;
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 HelloWorldServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
//super.service(req, resp);
//System.out.println("doget....");
PrintWriter out=resp.getWriter();
out.println("<html><head></head><body><center><font color='red'>HelloWorldServlet!</font></center></body></html>");
out.flush();//清理
out.close();//关闭
}
// @Override
// protected void doPost(HttpServletRequest req, HttpServletResponse resp)
// throws ServletException, IOException {
// // TODO Auto-generated method stub
// System.out.println("dopost...");
// //super.doPost(req, resp);
// doGet(req,resp);
// }
//
//
//
// @Override
// protected void doGet(HttpServletRequest req, HttpServletResponse resp)
// throws ServletException, IOException {
// // TODO Auto-generated method stub
// System.out.println("doget....");
// PrintWriter out=resp.getWriter();
// out.println("<html><head></head><body><center><font color='red'>HelloWorldServlet!</font></center></body></html>");
// out.flush();//清理
// out.close();//关闭
// }
/**
*
*/
private static final long serialVersionUID = 1L;//父类或者父类的父类实现了序列化的接口
}
然后index.html中get和post方法
<form action=http://localhost:8080/my/HelloWorldServlet method=get> <input type=text name=test> <input type=submit value="提交"> </form>
OR
<form action=http://localhost:8080/my/HelloWorldServlet method=post> <input type=text name=test> <input type=submit value="提交"> </form>
都可以显示