WEB（JSP）下的JDBC操作

Posted 2020-09-07

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了WEB（JSP）下的JDBC操作相关的知识，希望对你有一定的参考价值。

新建Web project名称为MyWebJDBC，在src文件夹下新建com.zss.www的包，并在包里建个java文件：DBConn；

在WebRoot下建立3个jsp文件。

在mysql中建立一个school的库，并在其建立表：information，表里包涵name,class。

DBConn代码如下：

package com.zss.www;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;


public class DBConn {     
     
  
    private  Connection conn=null;   
    private  PreparedStatement stmt=null;    
    private  ResultSet rs=null;    
 
    public DBConn(){     
    
    
        try {   
            String driver="com.mysql.jdbc.Driver"; 
            String url="jdbc:mysql://localhost:3306/school";  
            String user="root";  
            String password="11";  
            Class.forName(driver);     
            conn = (Connection) DriverManager.getConnection(url,user,password);  
            System.out.println("-------连接成功------");  
        } catch(ClassNotFoundException classnotfoundexception) {     
              classnotfoundexception.printStackTrace();     
            System.err.println("db: " + classnotfoundexception.getMessage());     
        } catch(SQLException sqlexception) {     
            System.err.println("db.getconn(): " + sqlexception.getMessage());     
        }        
    }     
  
    
    public DBConn(String driver,String url,String user,String password){     

        try {   
            //driver="com.mysql.jdbc.Driver"; 
            //url="jdbc:mysql://localhost:3306/school";  
            //user="root";  
            //password="11";  
            Class.forName(driver);     
            conn = (Connection) DriverManager.getConnection(url,user,password);  
            System.out.println("-------连接成功------");  
        } catch(ClassNotFoundException classnotfoundexception) {     
              classnotfoundexception.printStackTrace();     
            System.err.println("db: " + classnotfoundexception.getMessage());     
        } catch(SQLException sqlexception) {     
            System.err.println("db.getconn(): " + sqlexception.getMessage());     
        }     
        
    }   
    
    public void doInsert(String sql) {     
        try {     
            stmt = (PreparedStatement)conn.prepareStatement(sql);      
            int i = stmt.executeUpdate(sql);     
        } catch(SQLException sqlexception) {     
            System.err.println("db.executeInset:" + sqlexception.getMessage());     
        }finally{     
                 
        }     
    }     
  
    public void doDelete(String sql) {     
        try {     
           stmt = (PreparedStatement)conn.prepareStatement(sql);     
           int i = stmt.executeUpdate(sql);     
        } catch(SQLException sqlexception) {     
            System.err.println("db.executeDelete:" + sqlexception.getMessage());     
        }     
    }     
   
    public void doUpdate(String sql) {     
        try {     
            stmt = (PreparedStatement)conn.prepareStatement(sql);     
            int i = stmt.executeUpdate(sql);     
        } catch(SQLException sqlexception) {     
            System.err.println("db.executeUpdate:" + sqlexception.getMessage());     
        }     
    }     
  
    public ResultSet doSelect(String sql) {     
        try {  
            stmt = (PreparedStatement)conn.prepareStatement(sql);  
            rs = stmt.executeQuery(sql);   
            System.out.println("取得结果集");  
        } catch(SQLException sqlexception) {     
            System.err.println("db.executeQuery: " + sqlexception.getMessage());     
        }     
        return rs;     
    }     
    
     public void close(ResultSet rs) throws SQLException, Exception {     
    
       if (rs != null) {     
         rs.close();     
         rs = null;     
       }     
    
       if (stmt != null) {     
         stmt.close();     
         stmt = null;     
       }     
    
       if (conn != null) {     
         conn.close();     
         conn = null;     
       }     
     }     
    
     public void close() throws SQLException, Exception {     
       if (stmt != null) {     
         stmt.close();     
         stmt = null;     
       }     
    
       if (conn != null) {     
         conn.close();     
         conn = null;     
       }     
     }     
   
public static void main(String []args) throws Exception {  
      DBConn db=new DBConn();  
      ResultSet rs=db.doSelect("select * from dbuser where userNAME=‘chenjirong‘");  
      try {
        while(rs.next()) {
            System.out.println(rs.getString(1)); 
            System.out.println(rs.getString(2)); 
            System.out.println(rs.getString(3)); 
        }
       } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
       }  
  
      rs.close();
      db.close();
    }       
}

1.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>


<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP ‘1.jsp‘ starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
    <form name="form1" method="post" action="2.jsp">
  <p>name=
    <label for="textfield"></label>
    <input type="text" name="myname" id="textfield">
  </p>
  <p>class=
    <label for="textfield2"></label>
    <input type="text" name="myclass" id="textfield2">
  </p>
  <p>
    <input type="submit" name="button" id="button" value="提交">
  </p>
</form>
  </body>
</html>

2.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<jsp:useBean id="myjdbc01" scope="page"  class="com.zss.www.DBConn"/>
<%

request.setCharacterEncoding("utf-8");
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
String myname=request.getParameter("myname");
String myclass=request.getParameter("myclass");
%>    

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP ‘001.jsp‘ starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
   <%=myname%><br>
   <%=myclass%><br>
   
   
   
    <%
   String insertsql="insert into information(name,class) values(‘"+myname+"‘,‘"+myclass+"‘)";
   myjdbc01.doInsert(insertsql);
   myjdbc01.close();
     %>
    
    
    
  </body>
</html>

3.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="java.sql.*" %>
<%@ page import="com.mysql.jdbc.*" %>

<jsp:useBean id="myjdbc01" scope="page"  class="com.zss.www.DBConn"/>
<%

request.setCharacterEncoding("utf-8");
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>    

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP ‘001.jsp‘ starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>
  
  <body>
   

    <%
   String sql="select * from  information";
   ResultSet rs = myjdbc01.doSelect(sql);
        while (rs.next()) {
            out.println(rs.getString(1));
            out.println(rs.getString(2));
        }
 
     %>
    
    
  </body>
</html>