java web开发基础实例（javabean+jsp+servlet+jdbc）

JavaBean：用于传递数据，拥有与数据相关的逻辑处理

JSP：从Model接收数据并生成HTML

Servlet：接收HTTP请求并控制Model和View

jdbc：用于配置环境

一、【建立数据库】

在mysql中新建一个名为kecheng的数据库，并在其中新建一个kecheng数据表，包含三个字段，classname,classroom,teacher

二、【新建web项目】

1. eclipse新建一个名为kechengguanlli的Dynamic Web Project

修改class的默认输出目录为：WebContent/WEB-INF/classes,勾选自动生成web.xml

2. 将连接mysql的驱动jar包（mysql-connector-java-5.1.7-bin.jar）copy到WEB-INF下的lib目录下

3.  新建7个包

helper、链接数据库的操作，避免重复写代码，所以用一个包封装起来

SQL、数据库增删改查的统一代码，在实例中具体调用

javabean、基类，包括此项目中的成员变量

servlet、增加数据库中课程

servletdelete、删除数据库中课程

servletseclec、查询数据库中课程

servletupdate、修改数据库中课程

4. 新建类(最愉快的搬砖环节  -.-)，java类放在对应包中，jsp页面放在WebContent目录下，替换web.xml中内容；

helper包下新建 DbHelper.java

package helper;

import java.sql.Connection;
import java.sql.DriverManager;

public class DbHelper {
    private static String url = "jdbc:mysql://localhost:3306/kecheng";  //数据库地址
    private static String userName = "root";  //数据库用户名
    private static String passWord = "199812";  //数据库密码
    private static Connection conn = null;
    
    private DbHelper(){
        
    }
    
    public static Connection getConnection(){
        if(null == conn){
            try {
                Class.forName("com.mysql.jdbc.Driver");
                conn = DriverManager.getConnection(url, userName, passWord);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return conn;
    }
    
    public static void main(String[] args) {  //测试数据库是否连通
        System.out.println(getConnection());
    }
}

　javabean包下新建kecheng.java　

package javabean;

public class kecheng {
	private String classname;
	private String teacher;
	private String classroom;
	private String fanhui;
	public kecheng()
	{}
	public String getClassname() {
		return classname;
	}
	public void setClassname(String classname) {
		this.classname = classname;
	}
	public String getTeacher() {
		return teacher;
	}
	public void setTeacher(String teacher) {
		this.teacher = teacher;
	}
	public String getClassroom() {
		return classroom;
	}
	public void setClassroom(String classroom) {
		this.classroom = classroom;
	}
	public String getFanhui() {
		return fanhui;
	}
	public void setFanhui(String fanhui) {
		this.fanhui = fanhui;
	}
	

}

　servlet包下新建add.java　

package servlet;

import java.io.IOException;
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 javabean.kecheng;
import javabean.kecheng;
import SQL.sqlclass;

/**
 * Servlet implementation class add
 */
@WebServlet("/add")
public class add extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public add() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		int i=0,j=1,k=0;
		response.getWriter().append("Served at: ").append(request.getContextPath());
		String classname=request.getParameter("classname");//防止中文乱码
	 	 String teacher=request.getParameter("teacher");
	 	String classroom=request.getParameter("classroom");
	 	if(teacher.equals("王建民")||teacher.equals("刘立嘉")||teacher.equals("刘丹")||teacher.equals("王辉")||teacher.equals("杨子光"))
	 	i=1;
	 	String name;
        name=classroom.substring(0,2);
        if(name.equals("一教")||name.equals("二教")||name.equals("三教")||name.equals("基教"))
        j=1;
        if(true)//课程名
        	k=1;
       
        if(i==1&&j==1&&k==1)
	 	
        { kecheng student=new kecheng();
	 		student.setClassname(classname);
	 		student.setTeacher(teacher);
	 		student.setClassroom(classroom);
	 		sqlclass sql=new sqlclass();
	 		
	 	sql.addUser(student);
	 	response.sendRedirect("first.jsp");//页面跳转
        }
        else response.sendRedirect("add.jsp");
        
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

 【 jsp页面放在WebContent目录下】

first.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<center>课程基本信息管理主界面</center>
<center>——————————————————————————————————</center>
<a href="add.jsp"><center><b>课程信息录入</b></center></a><br>
<a href="update.jsp"><center><b>课程信息修改</b></center></a><br>
<a href="delete.jsp"><center><b>课程信息删除</b></center></a><br>
<a href="select.jsp"><center><b>课程信息查询</b></center></a><br>
</body>
</html>

　　

add.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="servlet.add" method="get">
<center>课程信息录入界面</center>
<center>——————————————————————————————————————</center>
<center>课程名称:<input type="text" name=classname><br></center>
<center>任课教师:<input type="text" name=teacher><br></center>
<center>上课地点:<input type="text" name=classroom><br></center>
<center><input type="submit" value="保存"></center>
</body>
</html>

　　

delete.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<center>课程信息删除</center>
<center>输入以下了表中的任意一个即可</center>
<center>——————————————————————————————————</center>
<form action="servletdelete.delete" method="get">
<center>课程名称:<input type="text" name=classname><br></center>
<center>任课教师:<input type="text" name=teacher><br></center>
<center>上课地点:<input type="text" name=classroom><br></center>
<center><input type="submit" value="确定删除"></center>
</body>
</html>

select.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@page import="java.util.*"%>  
<%@page import="javabean.kecheng"%>
<%@page import="SQL.sqlclass"%> 
<%@page import="java.util.List"%>  
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<center><%="课程"+"     "+"教师"+"     "+"教室" %> </center>
<%
sqlclass a=new sqlclass();
a.getAllUser();
kecheng c=new kecheng();
List<kecheng> b= new ArrayList<kecheng>();
b=a.getAllUser();
int i=0;
int j=0;
j=a.getnum();
for(;i<j;i++)
{c=b.get(i);
%>
 <center><%=c.getClassname()+"     "+c.getTeacher()+"     "+c.getClassroom() %> </center>

<% }%> 


</body>
</html>

　　update.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<center>课程信息修改</center>
<center>——————————————————————————————————</center>
<form action="servletupdate.update" method="get">
<center>课程名称:<input type="text" name=classname><br></center>
<center>任课教师:<input type="text" name=teacher><br></center>
<center>上课地点:<input type="text" name=classroom><br></center>
<center><input type="submit" value="保存"></center>
</body>
</html>

【替换web.xml中内容】

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
  <display-name>kechengguanli</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>servlet</servlet-name>
    <servlet-class>servlet.add</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>servlet</servlet-name>
    <url-pattern>/servlet.add</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>servletdelete</servlet-name>
    <servlet-class>servletdelete.delete</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>servletdelete</servlet-name>
    <url-pattern>/servletdelete.delete</url-pattern>
  </servlet-mapping>
  <servlet>
    <servlet-name>servletupdate</servlet-name>
    <servlet-class>servletupdate.update</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>servletupdate</servlet-name>
    <url-pattern>/servletupdate.update</url-pattern>
  </servlet-mapping>
</web-app>