Java 实现Mysql操作，基础的增删改查

 

 

 

package Mysql;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class startClass{

	
	  private String host="192.168.0.8";
	  private String DbName="java_chap02";
	  private String Uid="root";
	  private String Pwd="AAA@123";
  
  
  
  private Connection conn;//声明Connection引用
  private Statement stmt;//声明Statement引用
  private ResultSet rs;//声明结果集引用
  
 /**
  * 配置和打开数据库连接 
  */
    public void initialConnection()
    {
 
      try
      { 
    	   
    	  System.out.printf("Start Connect \n");
    	  
        Class.forName("com.mysql.cj.jdbc.Driver"); //jdbc mysql连接驱动
        
       String URL= String.format("jdbc:mysql://%s:3306/%s?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT", host,DbName);

 	  System.out.printf(URL+" \n");
       conn=DriverManager.getConnection(URL,Uid,Pwd);
        stmt=conn.createStatement();
        
        System.out.printf("Connect Suc \n");
      }
      catch(SQLException e)
      {
          System.out.printf("Connect Err  \n");
        e.printStackTrace();
      }
      catch(ClassNotFoundException e)
      {
          System.out.printf("Connect Err \n"+e.getMessage());  
        e.printStackTrace();
      }
    }

    /**
     * 关闭连接
     */
    public void closeConn()
    {
      try
      {
        if(rs!=null){rs.close();}
        if(stmt!=null){stmt.close();}
        if(conn!=null){conn.close();}
        
        System.out.printf("CloseConnect Suc \n");
      }
      catch(SQLException e)
      {
          System.out.printf("CloseConnect Err \n"+e.getMessage());  
      }
    }
    
    /**	
     * 插入数据方法
     */
    public void setInser() {
    	String sql="";
try {
	 startClass tem=new startClass();
     tem.initialConnection();

	  System.out.println("begin setInser 1");
	  
        sql="SELECT MAX(stu_id) as newKey from student";
        
        long KEY=0;
         
        tem.rs=tem.stmt.executeQuery(sql);
        if(tem.rs.next()){
        	KEY= tem.rs.getLong(1); 
          }
        
     for (int i = 0; i < 5; i++) {

   	  System.out.println("begin setInser::"+i);
           sql="INSERT into student VALUES ('"+(KEY+1+i)+"','"+i+"','"+i+"')";
      	  System.out.println(sql);
         var dd= tem.stmt.execute(sql);
         System.out.println(dd);
		}
     
     
     tem.closeConn();//关闭数据库连接
} catch (Exception ea) {
	// TODO: handle exception

    System.out.println(ea);
	
}
       
	}
    
    /**	
     * 修改数据方法
     */
    public void setUpd() {
    	String sql="";
try {
	 startClass tem=new startClass();
     tem.initialConnection();
 
	  
        sql="SELECT MAX(stu_id) as newKey from student";
        
        long KEY=0;
         
        tem.rs=tem.stmt.executeQuery(sql);
        if(tem.rs.next()){
        	KEY= tem.rs.getLong(1); 
          }
        
        sql="UPDATE	student SET stu_gender='999' WHERE stu_id='"+KEY+"'";
    	  System.out.println(sql);
       var dd= tem.stmt.execute(sql);
     
     tem.closeConn();//关闭数据库连接
} catch (Exception ea) {
	// TODO: handle exception

    System.out.println(ea);
	
}
       
	}
    /**	
     * 删除数据方法
     */
    public void setDel() {
    	String sql="";
try {
	 startClass tem=new startClass();
     tem.initialConnection();
 
	  
        sql="SELECT MAX(stu_id) as newKey from student";
        
        long KEY=0;
         
        tem.rs=tem.stmt.executeQuery(sql);
        if(tem.rs.next()){
        	KEY= tem.rs.getLong(1); 
          }
        
        sql="delete from 	student WHERE stu_id='"+(KEY-2)+"'";
    	  System.out.println(sql);
       var dd= tem.stmt.execute(sql);
     
     tem.closeConn();//关闭数据库连接
} catch (Exception ea) {
	// TODO: handle exception

    System.out.println(ea);
	
}
       
	}
    public static void main(String args[]){
    	 
       
       startClass tem=new startClass();
      String[] message=new String[3];
      String stu_id="103317012121";
      try
      {   
    	 
    	  
    	  //初始化数据库连接并更改密码
        tem.initialConnection(); 
        String sql="select stu_id,stu_name,stu_gender from student where stu_id='"+stu_id+"'";
        tem.rs=tem.stmt.executeQuery(sql);
        if(tem.rs.next()){
          message[0]=tem.rs.getString(1);
          message[1]=new String(tem.rs.getString(2).getBytes("gb2312"));
          message[2]=new String(tem.rs.getString(3).getBytes("gb2312"));
        }
        tem.closeConn();//关闭数据库连接
      }
      catch(Exception ea)
      {
        ea.printStackTrace();
      }
      
      
      System.out.println("begin setInser");
	  tem.setInser();
	  System.out.println("end setInser");
	  
	  System.out.println("begin setUpd");
	  tem.setUpd();
	  System.out.println("end setUpd");
	  
	  System.out.println("begin setDel");
	  tem.setDel();
	  System.out.println("end setDel");
	  
      /**	
       
      for(int i=0;i<3;i++)
      System.out.printf(message[i]+"\n");
      * 
       */
    }
} 

　　

执行结果