JDBC单元测试(一)-------main方法查询

新建java工程,添加mysql的jar包 

MainTest:

package com.test.example;

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

import com.test.util.JDBCUtil;

/**
 * 使用main方法执行单元测试
 * <p>Title: MainTest</p>
 * <p>Description: </p>
 * <p>Company: www.itcast.cn</p> 
 * @version 1.0
 */
public class MainTest {
	
	public static void main(String[] args) {
		
		//查询
		
		Connection connection = null;
		Statement statement = null;
		ResultSet resultSet = null;
		
		try {
			//1.获取连接对象
		   connection = JDBCUtil.getConn();
			//2.根据连接对象获取statement
		   statement = connection.createStatement();
			//3.执行sql语句,得到resultSet
			String sql = "select * from stu";
			resultSet = statement.executeQuery(sql);
			//4.遍历结果集
			while(resultSet.next()){
				
				String name = resultSet.getString("name");
				
				int age = resultSet.getInt("age");
				
				System.out.println("name="+name+",age="+age);
			}
		} catch (Exception e) {
			// TODO: handle exception
		}finally {
			JDBCUtil.close(connection, resultSet, statement);
		}
		
	}

}

JDBCUtil:

package com.test.util;

import java.io.FileInputStream;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class JDBCUtil {
	
	static String driverClass = null;
	static String url = null;
	static String name = null;
	static String password = null;
	
	//读取jdbc.properties
	static{
		try {
			//1.创建一个属性配置对象
			Properties properties = new Properties();
			
			//1.对应文件位于工程根目录  
			//InputStream is = new FileInputStream("jdbc.properties");
			
			//2.使用类加载器,读取drc下的资源文件  对应文件位于src目录底下  建议使用
			InputStream is = JDBCUtil.class.getClassLoader().getResourceAsStream("jdbc.properties");
			//2.导入输入流,抓取异常
			properties.load(is);
			//3.读取属性
			driverClass = properties.getProperty("driverClass");
			url = properties.getProperty("url");
			name = properties.getProperty("name");
			password = properties.getProperty("password");
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}
		
	}
	
	/**
	 * 注册驱动 建立参数
	 * <p>Title: close</p>
	 * <p>Description: </p>
	 * @param connection
	 * @param resultSet
	 * @param statement
	 */
	
	public static Connection getConn(){
			
		Connection connection = null;
		//2. 建立连接 参数一： 协议 + 访问的数据库 ， 参数二： 用户名 ， 参数三： 密码。
		 try {
			 //Class.forName(driverClass);可写可不写
			 //Class.forName(driverClass);
			connection = DriverManager.getConnection(url, name, password);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}	
		return connection;
		
	}
	
	/**
	 * 释放资源
	 * <p>Title: close</p>
	 * <p>Description: </p>
	 * @param connection
	 * @param resultSet
	 * @param statement
	 */
	public static void close(Connection connection,ResultSet resultSet,Statement statement){
		closeRS(resultSet);
		closeSt(statement);
		closeConn(connection);
		
	}
	
	private static void closeRS(ResultSet resultSet){
		try {
			if(resultSet !=null){
				resultSet.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			resultSet = null;
		}
	}
	
	private static void closeSt(Statement statement){
		try {
			if(statement !=null){
				statement.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			statement = null;
		}
	}
	
	private static void closeConn(Connection connection){
		try {
			if(connection !=null){
				connection.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			connection = null;
		}
	}
	


}

jdbc.properties:
 

driverClass=com.mysql.jdbc.Driver
url = jdbc:mysql://localhost/jdbc
name = root
password = root

数据库:

运行结果: