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java 连接MYSQL 进行查询怎么修改

2017-09-07 09:24:47  来源:网友分享
import java.sql.Connection ;import java.sql.DriverManager ;import java.sql.Statement ;public class shiyan4{	public static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;	public static final String DBURL = "jdbc:mysql://localhost:3306/ace" ;	public static final String DBUSER = "root" ;	public static final String DBPASS = "root" ;	public static void main(String args[]) throws Exception {  				Connection conn = null ; 				Statement stmt = null ;  				Class.forName(DBDRIVER) ;  				String sql = "SELECT user_name FROM users;";				conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;				stmt = conn.createStatement() ;   				stmt.executeUpdate(sql) ; 				stmt.close() ;  				conn.close() ;   	}}

请问这样怎么修改才能正常的进行查询 和在java上输出查询到的信息

解决方案

刚开始学习java时写的代码,oracle的,改成mysql的驱动和对应的用户名密码基本就可以了

package cn.database;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import oracle.jdbc.pool.OracleDataSource;public class DataBase {	private Connection conn = null;	private Statement stmt = null;	private ResultSet rs = null;	public DataBase() {				// oracle 的jdbc 连接		try {			OracleDataSource ds = new OracleDataSource();			ds.setUser("uamqas02");			ds.setPassword("uamqas02");			ds.setURL("jdbc:oracle:thin:@localhost:1521:devdb01");			conn = ds.getConnection();			stmt = conn.createStatement();		} catch (SQLException e) {			// TODO Auto-generated catch block			e.printStackTrace();		}	}	public ResultSet executeQuery(String sql) {		rs = null;		try {			// stmt=conn.createStatement();			rs = stmt.executeQuery(sql);		} catch (SQLException e) {			e.printStackTrace();			System.err.println("executeQuerty:" + e.getMessage());		}		return rs;	}	// ---------------------------数据库的更新、修改、删除操作-------------------------------------------------	public boolean executeUpdate(String sql) // 更新方法(增、删、改)	{		boolean temp = false;		try {			stmt = conn.createStatement();			int i = stmt.executeUpdate(sql);			if (i >= 1)				temp = true;		} catch (SQLException e) {			e.printStackTrace();			System.err.println("executeUpdate:" + e.getMessage());		}		return temp;	}	public boolean saveOrUpdateCommit(String sql, String sql2) {		boolean temp = true;		try {			conn.setAutoCommit(false);			stmt = conn.createStatement();			stmt.addBatch(sql);			stmt.addBatch(sql2);			stmt.executeBatch();			conn.commit();		} catch (SQLException e) {			// TODO Auto-generated catch block			e.printStackTrace();			temp = false;			// 回滚			try {				conn.rollback();			} catch (SQLException e1) {				// TODO Auto-generated catch block				e1.printStackTrace();			}		}		try {			conn.commit();		} catch (SQLException e) {			// TODO Auto-generated catch block			temp = false;			e.printStackTrace();		}		return temp;	}	public void closeStmt() {		try {			stmt.close();		} catch (SQLException e) {			e.printStackTrace();		}	}	public void closeConn() {		try {			conn.close();		} catch (SQLException e) {			e.printStackTrace();		}	}}