使用mybatis框架完成数据库中的CRUD（使用工具类）
mybatis框架的核心配置文件：创建一个名为resource的资源文件夹 ，用来存放配置文件
mybatis-config.xml的文件：
db.properties文件：
db_driverClassname=com.mysql.jdbc.Driver
db_url=jdbc:mysql://localhost:3306/test666
db_username=root
db_password=admin查看mybatis运行日志所需配置文件：文件名为:log4j.properties
log4j.rootLogger=ERROR, stdout
#log4j.rootLogger=NONE
log4j.logger.cn.itsource=TRACE
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
domain包域对象：
package cn.itsource.domain;
/**
* 域对象
* */
public class Product {
/**
* 商品id
* */
private Long id;
/**
* 商品名称
* */
private String productName;
/**
* 商品品牌
* */
private String brand;
/**
* 商品供应商
* */
private String supplier;
/**
* 商品零售价
* */
private Double salePrice;
/**
* 商品成本价
* */
private Double costPrice;
/**
* 商品折扣
* */
private Double cutoff;
/**
* 商品分类编号
* */
private Long dir_id;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
public String getSupplier() {
return supplier;
}
public void setSupplier(String supplier) {
this.supplier = supplier;
}
public Double getSalePrice() {
return salePrice;
}
public void setSalePrice(Double salePrice) {
this.salePrice = salePrice;
}
public Double getCostPrice() {
return costPrice;
}
public void setCostPrice(Double costPrice) {
this.costPrice = costPrice;
}
public Double getCutoff() {
return cutoff;
}
public void setCutoff(Double cutoff) {
this.cutoff = cutoff;
}
public Long getDir_id() {
return dir_id;
}
public void setDir_id(Long dir_id) {
this.dir_id = dir_id;
}
@Override
public String toString() {
return "Product [id=" + id + ", productName=" + productName + ", brand=" + brand + ", supplier=" + supplier
+ ", salePrice=" + salePrice + ", costPrice=" + costPrice + ", cutoff=" + cutoff + ", dir_id=" + dir_id
+ "]";
}
}配置对象关系映射文件（ProductMapper.xml）：用来写sql语句
insert into product (productName,dir_id,salePrice,supplier,brand,cutoff,costPrice)
values(#{productName},#{dir_id},#{salePrice},#{supplier},#{brand},#{cutoff},#{costPrice})
delete from product where id = #{id}
update product set productName=#{productName},dir_id=#{dir_id},
salePrice=#{salePrice},supplier=#{supplier},brand=#{brand},cutoff=#{cutoff},costPrice=#{costPrice}
where id = #{id}
dao层接口类：
package cn.itsource.dao;
import java.util.List;
import cn.itsource.domain.Product;
/**
* 完成商品的增删改查
* */
public interface IProductDao {
/**
* 添加商品
* */
void save(Product obj);
/**
* 修改商品信息
* */
void update(Product obj);
/**
* 删除商品
* */
void delete(Long id);
/**
* 查询单条商品信息
* */
Product queryOne(Long id);
/**
* 查询所有商品信息
* */
List queryAll();
}
测试类：
package cn.itsource.dao;
import java.util.List;
import org.junit.Test;
import cn.itsource.dao.impl.ProductDaoImpl;
import cn.itsource.domain.Product;
/**
* 测试类
* */
public class ProductDaoTest {
IProductDao dao = new ProductDaoImpl();
@Test
public void testSave() {
Product product = dao.queryOne(4L);
product.setProductName("苹果10");
product.setSalePrice(8000D);
dao.save(product);
}
@Test
public void testUpdate() {
Product product = dao.queryOne(10L);
product.setProductName("小米7777");
dao.update(product);
}
@Test
public void testDelete() {
dao.delete(20L);
}
@Test
public void testQueryOne() {
Product p = dao.queryOne(3L);
System.out.println(p);
}
@Test
public void testQueryAll() {
List ps = dao.queryAll();
for (Product product : ps) {
System.out.println(product);
}
}
}
工具类：
package cn.itsource.util;
import java.io.IOException;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public enum MyBatisUtil {
/**
* MyBatis三大核心对象特点：
* SqlSessionFactoryBuilder——创建了SqlSessionFactory后，这个类就不需要存在了
* SqlSessionFactory——被创建，SqlSessionFactory应该在你的应用执行期间都存在
* SqlSession——每个线程都应该有它自己的SqlSession实例。SqlSession的实例不能被共享，也是线程不安全的
* */
INSTANCE;
//SqlSessionFactory只需要一个
private static SqlSessionFactory factory;
/**
* 把factory放在静态代码块中的原因？
* 因为factory只需要创建一个，而静态代码块中的代码只会执行一次
* */
static{
try {
//创建一个SqlSession工厂对象，读取我们的核心配置文件
factory = new SqlSessionFactoryBuilder().build(Resources
.getResourceAsStream("mybatis-config.xml"));
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 直接返回一个SqlSession对象
* */
public SqlSession openSession(){
//通过SqlSessionFactory创建SqlSession对象
return factory.openSession();
}
}
package cn.itsource.dao.impl;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import cn.itsource.dao.IProductDao;
import cn.itsource.domain.Product;
import cn.itsource.util.MyBatisUtil;
public class ProductDaoImpl implements IProductDao {
@Override
public void save(Product obj) {
//通过MyBatisUtil工具类获取SqlSession
SqlSession session = MyBatisUtil.INSTANCE.openSession();
try {
//通过session直接执行sql语句
session.insert("cn.itsource.domain.ProductMapper.save", obj);
//提交事务
session.commit();
} catch (Exception e) {
session.rollback();
e.printStackTrace();
}finally {
session.close();
}
}
@Override
public void update(Product obj) {
//通过工具类获取SqlSession对象
SqlSession session = MyBatisUtil.INSTANCE.openSession();
try {
//通过session直接执行sql语句
session.update("cn.itsource.domain.ProductMapper.update", obj);
//提交事务
session.commit();
} catch (Exception e) {
session.rollback();
e.printStackTrace();
}finally {
session.close();
}
}
@Override
public void delete(Long id) {
//通过工具类获取SqlSession对象
SqlSession session = MyBatisUtil.INSTANCE.openSession();
try {
//通过session直接执行sql语句
session.delete("cn.itsource.domain.ProductMapper.delete", id);
//提交事务
session.commit();
} catch (Exception e) {
session.rollback();
e.printStackTrace();
}finally {
session.close();
}
}
@Override
public Product queryOne(Long id) {
Product p = null;
//通过工具类获取SqlSession对象
SqlSession session = MyBatisUtil.INSTANCE.openSession();
try {
//通过session直接执行sql语句 ，返回结果
p = session.selectOne("cn.itsource.domain.ProductMapper.selectOne", id);
} catch (Exception e) {
e.printStackTrace();
}finally {
session.close();
}
return p;
}
@Override
public List queryAll() {
List ps = new ArrayList<>();
//通过工具类获取SqlSession对象
SqlSession session = MyBatisUtil.INSTANCE.openSession();
try {
//通过session直接执行sql语句,返回结果
ps = session.selectList("cn.itsource.domain.ProductMapper.selectAll");
} catch (Exception e) {
e.printStackTrace();
}finally {
session.close();
}
return ps;
}
}