java 连接 mysql 的 步骤

第一步：下载mysql-connector-java并解压得到.jar文件

第二步：新建java项目 并倒入 .jar文件

 右键项目名-->build path-->add external archives ,就能添加了

第三部 java代码

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


public class DBHelper {
	public static final String driver="com.mysql.jdbc.Driver";
	public static final String url="jdbc:mysql://127.0.0.1/test0601";
	public static final String user="root";
	public static final String password="123456";
	
	public Connection conn=null;
	public PreparedStatement pst=null;
	
	public void open() {
		try{
			Class.forName(driver);
			conn=DriverManager.getConnection(url,user,password);
			if(!conn.isClosed())
				System.out.println("Succeeded connecting to the Database!");
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	public void close(){
		try{
			this.conn.close();
			
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	ResultSet query(String sql) throws SQLException{
		pst=conn.prepareStatement(sql);
		return pst.executeQuery();
		
	}
	
		
	
		
	


		
			
}

        

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


public class JDBCTest {
	static String sql=null;
	static DBHelper db=null;
	static ResultSet rs=null;
	public static void main(String[] args) throws SQLException {
		    db=new DBHelper();
		    db.open();
		    sql="select * from t1 where id<20";
		    rs=db.query(sql);
		    
			System.out.println("---------------");
			System.out.println("结果如下");
			int _id;
			try{
					while(rs.next()){
						_id= rs.getInt("id");
						System.out.println(_id);
					}
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			db.close();
	}
}

结果：