Servlet学习记录1

以下是servlet文件hiworld.java

其中doPost方法处理以post方式发送到数据。

 

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class hiworld extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public hiworld() {
        super();
    }

    /**
     * Destruction of the servlet.
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log

        // Put your code here

    }

    /**
     * The doGet method of the servlet.
     *
     * This method is called when a form has its tag value method equals to get.
     *
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */

    int count=0;
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        //建立输出类型

        response.setContentType("text/html");
        //得到输出流

        PrintWriter out = response.getWriter();
        int local_count;
        //实现local_count在多线程环境下的同步

        synchronized(this){
            local_count = ++count;
        }

        out.println("");
        out.println("");
        out.println(" A Servlet");
        out.println(" ");
        out.print(" This is ");
        out.print(this.getClass());
        out.println(", using the GET method");
        out.println("ok?");
        out.println("Accessed "+""+local_count+" times");
        out.println(" 
");
        out.println("");
        out.flush();
        out.close();
    }

    /**
     * The doPost method of the servlet.
     *
     * This method is called when a form has its tag value method equals to post.
     *
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        out.println("");
        out.println("");
        out.println(" A Servlet");
        out.println(" ");
        //获取以POST方式传递的表单中的参数名称

        Enumeration e = request.getParameterNames();
        while(e.hasMoreElements()){
            out.println("----------------------");
            out.println((String)e.nextElement());
            out.println("");
        }

        out.println("welcome "+ ""+ request.getParameter("username")+"" );

        out.print("");
        out.print(" This is ");
        out.print(this.getClass());
        out.println(", using the POST method");
        out.println(" ");
        out.println("");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet.
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here

    }

}

以下html代码以post方式提交表单内容给hiworld

 

<form method="post" action="/hi/servlet/hiworld" />
       <input type="text" name="username" />
       <input type="password" name="password" />
       <input type="submit" value="Post"/>
    </form>