JDBC工具类

package com.jdbc.demo3;

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

import org.junit.Test;

import com.jdbc.utils.JDBCUtils;

public class JDBCDemo3 {
@Test
/**
* 查询操作，使用工具类
*/
public void demo1() {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
//获得连接
conn =JDBCUtils.getConnection();
//创建执行SQL语句的对象
stmt = conn.createStatement();
//编写SQL；
String sql = "select * from user";
//执行查询
rs = stmt.executeQuery(sql);
//遍历结果集
while(rs.next()) {
System.out.println(rs.getInt("id") " " rs.getString("username") " " rs.getString("password"));
}
}catch(Exception e) {
e.printStackTrace();
}finally {
//释放资源
JDBCUtils.release(rs, stmt,conn);
}
}

}