使用sqlyou在mysql的自带test库创建一张表，sql脚本如下
USE test;
CREATE TABLE product(
id INT(11) NOT NULL AUTO_INCREMENT,
product_name VARCHAR(200)NOT NULL,
store INT(11),
created DATE DEFAULT NULL,
updated DATE DEFAULT NULL,
PRIMARY KEY(id)
)DEFAULT CHARSET=utf8;
INSERT INTO product VALUES
(NULL,'apple',50,NOW(),NOW()),
(NULL,'pear',60,NOW(),NOW());
创建后表如图
创建maven项目
抽出数据库的配置
项目结构
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.mybatis</groupId>
<artifactId>mybatis-basic2</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.8</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.40</version>
</dependency>
</dependencies>
</project>
dbconfig.properties
driver=com.mysql.jdbc.Driver
url=jdbc:mysql:///test
username=root
password=g
mybatis-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--dtd约束属于xml文档约束，通过dtd定义文档中的元素都有哪些，这些元素的嵌套关系是怎样的，这些元素的先后顺序是怎样的 -->
<configuration>
<!-- 关联properties文件 -->
<properties resource="dbconfig.properties" />
<settings>
<!--启用缓存(有的默认就是开启的) -->
<setting name="cacheEnabled" value="true" />
<!--开启驼峰规则 -->
<setting name="mapUnderscoreToCamelCase" value="true" />
</settings>
<typeAliases>
<!--设置类的别名 默认为指定包中的类定义一个别名，这个别名为类名的第一个单词的首字母小写 -->
<package name="com.project.pojo" />
</typeAliases>
<!--配置开发环境 -->
<environments default="development">
<environment id="development">
<!--事务管理环境 -->
<transactionManager type="JDBC" />
<!--配置数据源 -->
<dataSource type="POOLED">
<property name="driver" value="${driver}" />
<property name="url" value="${url}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/ProductMapper.xml" />
</mappers>
</configuration>
ProductMapper.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--mybatis中的映射文件 -->
<!--定义一个sql查询，sql查询必须有一个id,其中resultType表示查询结果会封装到对应的map类型中,一行记录对应一个map -->
<mapper namespace="com.project.dao.ProductDao">
<select id="findAll" resultType="product">
select * from product
</select>
</mapper>
Product.java
package com.project.pojo;
import java.util.Date;
public class Product {
private Integer id;
private String productName;
private Integer store;
private Date created;
private Date updated;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public Integer getStore() {
return store;
}
public void setStore(Integer store) {
this.store = store;
}
public Date getCreated() {
return created;
}
public void setCreated(Date created) {
this.created = created;
}
public Date getUpdated() {
return updated;
}
public void setUpdated(Date updated) {
this.updated = updated;
}
@Override
public String toString() {
return "Product [id=" + id + ", productName=" + productName + ", store=" + store + ", created=" + created
+ ", updated=" + updated + "]";
}
}
ProductDao.java
package com.project.dao;
import java.util.List;
import com.project.pojo.Product;
public interface ProductDao {
/**
* 接口中方法名要与mapper文件中sqlid相同
* 返回值类型要与sqlid对象的返回值类型匹配
* @return
*/
List<Product>findAll();
}
TestProduct.java
package com.project.test;
import java.io.IOException;
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 com.project.dao.ProductDao;
import com.project.pojo.Product;
public class TestProduct {
private static SqlSessionFactory factory;
public static void init() throws IOException{
factory=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
}
public static void findAll()throws IOException{
init();
SqlSession session=factory.openSession();
//通过session获取一个dao对象
ProductDao dao = session.getMapper(ProductDao.class);
List<Product> list = dao.findAll();
System.out.println(list);
//释放资源
session.close();
}
public static void main(String[] args) {
try {
findAll();
} catch (Exception e) {
e.printStackTrace();
}
}
}
运行结果
[Product [id=1, productName=apple, store=50, created=Mon Mar 11 00:00:00 CST 2019, updated=Mon Mar 11 00:00:00 CST 2019], Product [id=2, productName=pear, store=60, created=Mon Mar 11 00:00:00 CST 2019, updated=Mon Mar 11 00:00:00 CST 2019]]
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