连接数据库并进行简单查询

ackage com.my_java_oracle;

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

public class conn {
public static void main(String[] args) {
//加载驱动
try {
Class.forName(“oracle.jdbc.driver.OracleDriver”);

	//获取数据库连接
	try {
		Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORCL", "scott", "123");
	
		//获取数据库执行对象
		Statement sata = conn.createStatement();
		
		//定义sql语句
		String sql="select empno,ename,sal from emp";
		
		//执行语句
		ResultSet rs = sata.executeQuery(sql);
		
		//表头
		System.out.println("编号"+"\t"+"姓名"+"\t"+"薪水");
		//遍历查询结果
		while(rs.next()) {
			int empno=rs.getInt(1);
			String ename=rs.getString(2);
			double sal=rs.getDouble(3);
			
			//数据查询结果
			System.out.println(empno+"\t"+ename+"\t"+sal);
		}
		//关闭资源
		sata.close();
		conn.close();
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	
	
} catch (ClassNotFoundException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}

}
}
//prepareStatement简单使用
package com.my_java_oracle;

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

public class prepareStatement {
public static void main(String[] args) {
try {
Class.forName(“oracle.jdbc.driver.OracleDriver”);

	try {
		Connection conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORCL", "scott", "123");
	
		String sql="update emp set sal=? where ename=?";
		PreparedStatement prst = conn.prepareStatement(sql);
		prst.setInt(1, 800);
		prst.setString(2, "SMITH");
		
		int row=prst.executeUpdate();
		if(row>0) {
			System.out.println("更改成功");
		}else {
			System.out.println("更改失败");
		}
		prst.close();
		conn.close();
		
		
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	
} catch (ClassNotFoundException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}

}
}