Java Servlet基础示例-优快云博客

本文介绍了Java Servlet的基础配置与使用方法，包括简单的Servlet开发配置示例及如何通过表单提交调用Servlet。提供了完整的代码示例，帮助读者快速上手。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

1.简单servlet开发配置示例

java servlet API包括2个基本的包，javax.servlet和javax.servlet.http。其中javax.servlet提供了用来控制servlet生命周期所需的类和接口，是编写servlet必须的。javax.servlet.http提供了处理与http相关的类和接口，每个servlet必须实现servlet接口。

//---------------HelloWorld.java---------------

package servlets;

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 HelloWorld extends HttpServlet {

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

  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
  out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
  out.println("<HTML>");
  out.println(" <HEAD><TITLE>Hello World!</TITLE></HEAD>");
  out.println(" <BODY>");
  out.print(" <h1>Hello World<h1> ");
  out.println(" </BODY>");
  out.println("</HTML>");
  out.flush();
  out.close();
}
}

//--------------------WEB-XML------------------

<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>/HelloWorld</url-pattern>
</servlet-mapping>
</web-app>

-输入http://127.0.0.1:8080/servletConfig/HelloWorld

显示Hello World

2.JSP页面调用Servlet的方法

在HelloWorld程序中直接输入Servlet的地址进行访问。而在实际应用中这样是不行的，是通过调用Servlet进行访问，下面介绍两种调用Servlet的方法。

（1）通过表单提交调用Servlet

通过表单提交调用Servlet时，把表单action指向对应的Servlet即可。

//------------------------form.jsp----------------

<%@ page language="java" pageEncoding="gbk"%>
<head>
    <html:base />
    <title>form.jsp</title>
</head>
<body>
    <html:form action="AcceptForm" method="post" focus="login">
      <table border="0">
        <tr>
          <td>姓名:</td>
          <td><html:text name="login" /></td>
        </tr>
        <tr>
          <td>密码:</td>
          <td><html:password name="password" /></td>
        </tr>
        <tr>
          <td colspan="2" align="middle"><html:submit value="提交"/></td>
        </tr>
      </table>
    </html:form>
</body>
</html:html>

//---------------AcceptForm.java--------------

package servlets;

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;

class AcceptForm extends HttpServlet {

public AcceptForm() {
super();
}

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

  response.setContentType("text/html");
  response.setCharacterEncoding("gbk");
  PrintWriter out = response.getWriter();
  String login = new String(request.getParameter("login").getBytes("iso-8859-1"));//避免中文乱码进行了强制转换，最好写过滤器
  String password =new String( request.getParameter("password").getBytes("iso-8859-1"));

  out.print("    提交的表单内容为 ");
  out.print("姓名：" + login);
  out.println("密码："+password);

}

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

doGet(request, response);
}

}

//----------WEB-XML-------------

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>AcceptForm</servlet-name>
<servlet-class>servlets.AcceptForm</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AcceptForm</servlet-name>
<url-pattern>/AcceptForm</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<login-config>
<auth-method>BASIC</auth-method>
</login-config>
</web-app>

servlet用法