【作业Day02】JDBC-MySQL的增删改查功能实现

JDBC-MySQL的增删改查功能实现

通过navicat连接上mysql以后
先建立一个新数据库

格式如下

1.建立properties文件

便于后期快速修改，降低耦合度

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/jdbc_db?rewriteBatchedStatements=true
username=root
password=123456

2.建立domain

package com.wzbc.jdbc.domain;

public class Student {
	Integer id;
	String name;
	Integer age;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";
	}
	
	
}

3.建立DAO接口

package com.wzbc.jdbc.dao;

import java.util.List;

import com.wzbc.jdbc.domain.Student;

public interface IStudentDao {
	/**
	 * 保存一个学生
	 */
	public void save(Student stu);
	/**
	 * 删除学生
	 */
	public void delete(int id);
	/**
	 * 更新一个学生信息
	 */
	public void update(int id,Student stu);
	/**
	 * 获取指定学生
	 */
	public Student get(int id);

4.建立JDBCUtils.java文件（工具类）

package com.wzbc.jdbc.util;

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

import javax.sql.DataSource;


import com.alibaba.druid.pool.DruidDataSourceFactory;

public class JdbcUtil {

	public static DataSource ds = null;
	static {
		try {
			//1.加载配置文件
			Properties p = new Properties();
			FileInputStream in = new FileInputStream("resource/db.properties");
			p.load(in);
			ds = DruidDataSourceFactory.createDataSource(p);
		}catch(Exception e) {
			e.printStackTrace();
		}
	}
	
	public static DataSource getDataSource() {
		return ds;
	}
	
	
	public static Connection getConn() {
		try {
			// 2.连接数据
			return ds.getConnection();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
	/**
	 * 关闭资源 
	 */
	public static void close(Connection conn,Statement st,ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {

				e.printStackTrace();
			}
		}
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	
}

5.接口实现类

package com.wzbc.jdbc.dao.impl;
import java.sql.SQLException;
import java.util.List;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;

import com.wzbc.jdbc.dao.IStudentDao;
import com.wzbc.jdbc.domain.Student;
import com.wzbc.jdbc.util.JdbcUtil;

public class StudentDaoImpl implements IStudentDao {
	@Override
	public void save(Student stu) {
		String sql = "insert into student(name,age) values(?,?)";
		QueryRunner qr = new QueryRunner(JdbcUtil.getDataSource());
		try {
			qr.update(sql, stu.getName(),stu.getAge());
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	@Override
	public void delete(int id) {
		// 3.创建语句
		String sql = "delete from student where id = ?";
	}
	@Override
	public void update(int id, Student stu) {
		String sql = "update student set name=?, age=? where id =? ";
	}
	@Override
	public Student get(int id) {
		String sql = "select * from student where id = ?";
		QueryRunner qr = new QueryRunner(JdbcUtil.getDataSource());
		try {
			return   qr.query(sql, new BeanHandler<Student>(Student.class),id);
		} catch (SQLException e) {
			e.printStackTrace();
			return null;
		}
	}
}

6.测试类

package com.wzbc.jdbc.test;

import java.util.List;

import org.junit.Test;

import com.wzbc.jdbc.dao.IStudentDao;
import com.wzbc.jdbc.dao.impl.StudentDaoImpl;
import com.wzbc.jdbc.domain.Student;

public class StudentDaoTest {
	@Test
	public void save() {
		// 创建一个学生
		Student stu = new Student();
		stu.setName("李白100");
		stu.setAge(21);
		// 把学生保存到数据库当中
		IStudentDao dao = new StudentDaoImpl();
		dao.save(stu);
	}

	@Test
	public void delete() {
		IStudentDao dao = new StudentDaoImpl();
		dao.delete(10);
	}

	@Test
	public void update() {
		IStudentDao dao = new StudentDaoImpl();
		// 创建一个学生
		Student stu = new Student();
		stu.setName("鲁班7");
		stu.setAge(7);	
		dao.update(9, stu);
		
	}
	@Test
	public void get(){
		IStudentDao dao = new StudentDaoImpl();
		 Student stu = dao.get(2);
		 System.out.println(stu);
	}
}