Servlet获取GET或者POST的参数

fcp — Sat, 13 Dec 2008 00:47:00 GMT

简单小程序，就是在页面里显示出POST或者GET

1，request.getMethod()，获得调用页面的方法
2，Enumeration e = request.getParameterNames();接收所有的参数的名称，并且存在一个Enumeration里
3，parameterValue = request.getParameter(parameterName); 循环这句话，获取所有的参数的值

package com.fcp.web2;

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 ShowParameter extends HttpServlet {

    /**
     *
     */
    private static final long serialVersionUID = -3484338400290863566L;

    /**
     * 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
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out
                .println(""-//W3C//DTD HTML 4.01 Transitional//EN\">");
        out.println("");
        out.println("  A Servlet");
        out.println("  ");
        this.printMethod(request, response);
        this.printParameters(request, response);
        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(""-//W3C//DTD HTML 4.01 Transitional//EN\">");
        out.println("");
        out.println("  A Servlet");
        out.println("  ");
        this.printMethod(request, response);
        this.printParameters(request, response);
        out.println("  ");
        out.println("");
        out.flush();
        out.close();
    }

    private void printMethod(HttpServletRequest request, HttpServletResponse response) throws IOException
    {
        PrintWriter out = response.getWriter();
        out.println("Method: " + request.getMethod() + "
");
    }

    private void printParameters(HttpServletRequest request, HttpServletResponse response) throws IOException
    {
        PrintWriter out = response.getWriter();
        Enumeration<String> e = request.getParameterNames();
        String parameterName, parameterValue;
        while(e.hasMoreElements())
        {
            parameterName = e.nextElement();
            parameterValue = request.getParameter(parameterName);
            out.println(parameterName + ": " + parameterValue + "
");
        }
    }

}

fcp 2008-12-13 08:47 发表评论

手工编写Servlet

fcp — Sun, 30 Nov 2008 21:19:00 GMT

从今天开始，复习原来学过的东东，基本上都忘了，从基础开始
万丈高楼平地起，|||...

手工编写Servlet
1， what is servlet
说白了就一个能响应用户请求的java程序，可以回应给用户HTML代码，当然也可以执行其他任务，比如操纵数据库什么的。

2，编写Servlet
其实就是个Java文件，需要继承HttpServlet这个类，位置是在javax.servlet.http.HttpServlet

package com.fcp.hello;

import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import java.util.*;

public class HelloServlet extends HttpServlet
{
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        response.setContentType("text/html;charset=utf-8");

        PrintWriter out = response.getWriter();
        out.println("");
        out.println("");
        out.println("my first servlet");
        out.println("");
        out.println("");
        //print time
        out.println(new Date());
        out.println("
");
        out.println("Welcome to my first Servlet!");
        out.println("");
        out.println("");
        out.flush();
        out.close();
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
        doGet(request, response);
    }
}

重写doGet和doPost这两个函数，来处理GET和POST请求
response这个变量就是要返回给用户的，所以先设置一下返回数据的类型
response.setContentType("text/html;charset=utf-8");

然后获得PrintWriter这个对象的实例
PrintWriter out = response.getWriter();

恩，现在可以输出我们想输出的内容了
输出完别忘了，flush和close

在doPost方法里调用doGet，这样可以让GET和POST方法得到同样的处理

2，编译程序
因为Tomcat能接受的已经编译的class文件，所以我们要先进行编译
javac -d . HelloServlet.java

运行后有错误。。。。找不到javax.servlet.http.HttpServlet
传输中是没有装j2ee

这个包我们可以在tomcat中找到，导致我现在还不知道正常的装法
重新编译，加上class path
javac -d . -cp c:\tomcat6\lib\servlet-apt.jar HelloServlet.java
编译成功

3，创建tomcat的目录结构
在webapps下建立自己的web应用
-hello
    |-WEB-INF
        |-web.xml
        |-classes
            |-com
                |-fcp
                    |-hello
                        |-HelloServlet.class

4，建立web.xml文件

xml version="1.0" encoding="ISO-8859-1"?>

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">

    <servlet>
        <servlet-name>helloservlet-name>
        <servlet-class>com.fcp.hello.HelloServletservlet-class>
    servlet>

    <servlet-mapping>
        <servlet-name>helloservlet-name>
        <url-pattern>/hellourl-pattern>
    servlet-mapping>

web-app>

前面的xml声明是从conf/web.xml中copy的
后面的才是主要内容
就是定义servlet，定义servlet的名字和对应的类

就是定义哪个servlet和哪个URL对应

5，启动tomcat，查看对应的URL
http://localhost:8080/htllo/hello
应该就可以看见了

fcp 2008-12-01 05:19 发表评论

BlogJava-我要去google-文章分类-j2ee

Servlet获取GET或者POST的参数

手工编写Servlet