获取自增长键值

需求

1. 插入一条数据，将插入数据的自增长键值返回回来

   代码演示

2. Java代码 ```java package com.wisdom.java;

import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Statement;

public class TestGenerateKey { public static void main(String[] args) throws Exception{ // 注册驱动 Class.forName(“com.mysql.jdbc.Driver”);

    // 连接数据库
    String url = "jdbc:mysql://192.168.160.131:3306/subquery";
    Connection conn = DriverManager.getConnection(url,"root","数据库密码");
    // 操作数据库
    String sql = "insert into dept values(?,?,?)";
    PreparedStatement pre = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
    pre.setObject(1, null);
    pre.setObject(2, "MANAGER");
    pre.setObject(3, "BJ");
    int executeUpdate = pre.executeUpdate();
    // 获取插入的自增长值
    ResultSet generatedKeys = pre.getGeneratedKeys();
    if(generatedKeys.next()){
        System.out.println(generatedKeys.getObject(1));
    }
    // 关闭资源
    generatedKeys.close();
    pre.close();
    conn.close();
}

}

```