java如何用jdbc连接mysql数据库

Posted 2021-07-27 轻烟散入五侯家

下面提供了一个可以连接的类，并简单写了几个方法，使用时根据实际写方法，实例化这个类后调用相应方法即可

package workpackage2;

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

public class mysqlHandlerModuleClass {
	Statement stmt;
	Connection con;
	public MysqlHandlerModuleClass() throws Exception {
		Class.forName("com.mysql.cj.jdbc.Driver");
		String user = "root";//这里填入实际的mysql用户名
		String pwd = "root";//这里填入实际的mysql用户密码
		String url = "jdbc:mysql://localhost:3306/pai_database?characterEncoding=utf8&useSSL=false&serverTimezone=UTC&rewriteBatchedStatements=true";
	
		con = DriverManager.getConnection(url,user,pwd);
		stmt = con.createStatement();
	}
	
	//判断mysql中column_name这列数据是否存在数据data1的示例,存在返回true,反之false
	public Boolean judgeDataInMysql(String tableNameOfMysql, String data1) throws Exception {
		String inquireSentence = String.format("SELECT * FROM %s WHERE column_name = %s;", tableNameOfMysql, data1);//查询语句
		
		ResultSet rs = stmt.executeQuery(inquireSentence);
		if (rs.next()) {
			return true;
		}else {
			return false;
		}
	}
	
	//往数据库（不重复）插入数据的方法示例
	public void insertDataToMysql(String tableNameOfMysql, String data1, int data2) throws Exception {
		String insertSentence = String.format("INSERT IGNORE INTO %s VALUES ('%s',%s);", tableNameOfMysql, data1, data2 );//插入语句
		stmt.executeUpdate(insertSentence);
	}
	
	//关闭jdbc与Mysql连接的方法
	public void closeMysqlConnection() throws Exception {
		stmt.close();
		con.close();
	}

}