JAVA JDBC的使用

JDBC：是官方定义大的一套操作所有关系型数据库的规则，即接口

MySQL驱动jar包的下载方式：
地址：https://dev.mysql.com/downloads/

选择platform independent下载

JDBC使用步骤：
1.导入驱动jar包：复制到项目下的libs目录下，并且Add As Library
2.注册驱动
3.获取数据库连接对象Connection
4.定义sql
5.获取执行sql语句的对象statement
6.执行sql，接收返回结果
7.处理结果
8.释放资源

给数据表插入一条数据：

package test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class jdbcdem2 {
    public static void main(String[] args) {
        Statement stmt = null;
        Connection conn = null;
        try {
            //1.注册驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.定义sql
            String sql = "insert into student values('zdbc','zdbc')";
            //3.获取Connection对象
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/live","root","1234");
            //4.获取执行sql的对象
            stmt = conn.createStatement();
            //5.执行sql
            int count = stmt.executeUpdate(sql);
            //6.处理结果
            System.out.println(count);
            if(count>0){
                System.out.println("添加成功");
            }
            else {
                System.out.println("添加失败");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            //8.释放资源
            if(stmt!=null){
                try {
                    stmt.close();
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }

            if(conn!=null){
                try {
                    conn.close();
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
        }
    }
}

查询数据：

package test;

import java.sql.*;

public class jdbcdem3 {
    public static void main(String[] args) {
        Statement stmt = null;
        Connection conn = null;
        ResultSet rs =null;
        try {
            //1.注册驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.定义sql
            String sql = "select * from student";
            //3.获取Connection对象
            conn = DriverManager.getConnection("jdbc:mysql:///live","root","1234");
            //4.获取执行sql的对象
            stmt = conn.createStatement();
            //5.执行sql
            rs = stmt.executeQuery(sql);
            //6.处理结果
            while (rs.next()){
            	int id = rs.getInt("id");
                String name = rs.getString("num");
                String pass = rs.getString("pass");
                System.out.println(name+'-'+pass);
            }

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            //8.释放资源
            if(rs!=null){
                try {
                    rs.close();
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
            if(stmt!=null){
                try {
                    stmt.close();
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }

            if(conn!=null){
                try {
                    conn.close();
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
        }
    }
}