文章目录

文章目录

• 文章目录
• 一、jdbc入门案例
• 二、JDBC-API详解
• • 1.DriverManager
  • 2.Connection
  • 3.Statement
  • 4.ResultSet
  • 5.PreparedStatement
• 三、数据库连接池
• • 1.简介
  • 2.使用

一、jdbc入门案例

案例：

package com.study;import java.sql.Connection;import java.sql.DriverManager;import java.sql.Statement;public class TestOne {    public static void main(String[] args) throws Exception { //注册驱动 Class.forName("com.mysql.jdbc.Driver"); //获取连接 String url="jdbc:mysql://localhost/jdbcone"; String userName="root"; String passWord="root"; Connection conn = DriverManager.getConnection(url, userName, passWord); //定义sql String sql="update users set password=666 where id=1"; //获取执行sql的statement对象 Statement stmt = conn.createStatement(); //执行sql int count = stmt.executeUpdate(sql); //受影响的行数 //处理结果 System.out.println("受影响的行数："+count);  //受影响的行数：1 //释放资源 stmt.close(); conn.close();    }}

二、JDBC-API详解

1.DriverManager

2.Connection

案例：

package com.study;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;import java.sql.Statement;public class TestOne {    public static void main(String[] args) throws Exception { //注册驱动 Class.forName("com.mysql.jdbc.Driver"); //获取连接 String url="jdbc:mysql://localhost/jdbcone"; String userName="root"; String passWord="root"; Connection conn = DriverManager.getConnection(url, userName, passWord); Statement stmt =null; try {     //开启事务     conn.setAutoCommit(false);     //定义sql     String sql1="update users set password=888 where id=1";     String sql2="update users set password=666 where id=2";     //获取执行sql的statement对象     stmt = conn.createStatement();     //执行sql     int count1 = stmt.executeUpdate(sql1); //受影响的行数     //处理结果     System.out.println("受影响的行数："+count1);  //受影响的行数：1     int count2 = stmt.executeUpdate(sql2); //受影响的行数     //处理结果     System.out.println("受影响的行数："+count2);  //受影响的行数：1     //提交事务     conn.commit(); } catch (Exception e) {     //回滚事务     conn.rollback();     e.printStackTrace(); } //释放资源 stmt.close(); conn.close();    }}/*受影响的行数：1受影响的行数：1 */

3.Statement

4.ResultSet

案例1：

package com.study;import java.sql.*;public class ResultSetTest {    public static void main(String[] args) throws Exception { //注册驱动 Class.forName("com.mysql.jdbc.Driver"); //获取连接 String url="jdbc:mysql://localhost/jdbcone"; String userName="root"; String passWord="root"; Connection conn = DriverManager.getConnection(url, userName, passWord); Statement stmt = null; ResultSet rs = null; try {     //定义sql     String sql="select * from users";     //创建statement对象     stmt = conn.createStatement();     //执行sql语句     rs = stmt.executeQuery(sql);     //遍历rs中的数据     while (rs.next()){  int id = rs.getInt("id");  String name = rs.getString("username");  String password = rs.getString("password");  String email= rs.getString("email");  System.out.println(id);  System.out.println(name);  System.out.println(password);  System.out.println(email);  System.out.println("----------------------------------------");     } } catch (Exception e) {     e.printStackTrace(); } //释放资源 rs.close(); stmt.close(); conn.close();    }}

案例2：

package com.study;import java.sql.*;import java.util.ArrayList;import java.util.List;public class ResultSetTestPlus {    public static void main(String[] args) throws Exception{ //注册驱动 Class.forName("com.mysql.jdbc.Driver"); //获取连接 String url="jdbc:mysql://localhost/jdbcone"; String userName="root"; String passWord="root"; Connection conn = DriverManager.getConnection(url, userName, passWord); Statement stmt = null; ResultSet rs = null; //创建集合对象List<Account> list=new ArrayList<>(); try {     //定义sql     String sql="select * from users";     //创建statement对象     stmt = conn.createStatement();     //执行sql语句     rs = stmt.executeQuery(sql);     //遍历rs中的数据     while (rs.next()){  Account account=new Account();  int id = rs.getInt("id");  String name = rs.getString("username");  String password = rs.getString("password");  String email= rs.getString("email");  //赋值  account.setId(id);  account.setUsername(name);  account.setPassword(password);  account.setEmail(email);  //存入集合  list.add(account);//  [Account{id=1, username='小马哥', password='888', email='[email protected]'}, Account{id=2, username='小飞侠',//  password='666', email='[email protected]'}, Account{id=3, username='马奎斯', password='333', email='[email protected]'}]     }     //打印集合     System.out.println(list); } catch (Exception e) {     e.printStackTrace(); } //释放资源 rs.close(); stmt.close(); conn.close();    }    }

5.PreparedStatement

案例：

package com.study;import java.sql.*;public class PreparedStatementLogin {    public static void main(String[] args) throws Exception { //注册驱动 Class.forName("com.mysql.jdbc.Driver"); //获取连接 String url="jdbc:mysql://localhost/jdbcone"; String userName="root"; String passWord="root"; Connection conn = DriverManager.getConnection(url, userName, passWord); //接收用户输入的用户名和密码 String name="king"; String psw="888"; String sql="select * from users where username=? and password=?"; //创建pstmt对象 PreparedStatement pstmt = conn.prepareStatement(sql); //设置值 pstmt.setString(1,name); pstmt.setString(2,psw); //执行sql语句 ResultSet rs = pstmt.executeQuery(); //判断是否登录成功 if (rs.next()){     System.out.println("登录成功！"); } else {     System.out.println("登录失败！"); } rs.close(); pstmt.close(); conn.close();    }    }//登录成功！

三、数据库连接池

1.简介

2.使用

案例：

driverClassName=com.mysql.jdbc.Driverurl=jdbc:mysql:///usersusername=rootpassword=root# 初始化连接数initialSize=5# 最大连接数maxActive=10# 最大等地时间maxWait=3000package com.druidTest;import com.alibaba.druid.pool.DruidDataSourceFactory;import javafx.scene.layout.Priority;import javax.sql.DataSource;import java.io.FileInputStream;import java.sql.Connection;import java.util.Properties;public class DruidTest {    public static void main(String[] args) throws Exception { //导入jar包 //定义配置文件 //加载配置文件 Properties prop = new Properties(); prop.load(new FileInputStream("JDBCTest/src/druid.properties")); //获取连接池对象 DataSource dataSource = DruidDataSourceFactory.createDataSource(prop); //获取数据库连接Connection Connection conn = dataSource.getConnection(); System.out.println(conn);    }}

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