走进JavaWeb技术世界14：Mybatis入门

<?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">  

<mapper namespace="com.mybatis.UserMapper">  

    <select id="findById" parameterType="int" resultType="User">  
        select user_id id,user_name userName,user_age age from t_user where user_id=#{id}  
    </select>  

</mapper> 

<configuration>
    
    <properties resource="db.properties"></properties>
    <environments default="development">
        <environment id="development">
            
            <transactionManager type="JDBC"></transactionManager>
            
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
    </environments>
</configuration>

<!DOCTYPE mapper
    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.sl.dao.ProductDao">
    
    <select id="selectProductById" resultType="com.sl.po.Product" parameterType="int">
      select * from products where id = #{id} </select>
</mapper>

<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.sl</groupId>
    <artifactId>mybatis-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <properties>
        <junit.version>4.12</junit.version>
        <mybatis.version>3.4.1</mybatis.version>
        <mysql.version>5.1.32</mysql.version>
        <log4j.version>1.2.17</log4j.version>
    </properties>
    <dependencies>
        
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            
        </dependency>
        
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>${mybatis.version}</version>
        </dependency>
        
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
    </dependencies>
</project>

<?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">
<configuration>

    <properties resource="db.properties"></properties>
    <environments default="development">
        
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}" />
                <property name="password" value="${jdbc.password}" />
            </dataSource>
        </environment>
    </environments>
     <!—申明mapper文件 -->
        <mappers>
        
        <mapper resource="mapper/productMapper.xml"></mapper>
    </mappers>
</configuration>

<?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">
<mapper namespace="com.sl.mapper.ProductMapper">

    <select id="selectAllProduct" resultType="com.sl.po.Product"> select * from products </select>

</mapper>

//使用productMapper.xml配置文件
public class TestClient { //定义会话SqlSession
    SqlSession session =null;

    @Before public void init() throws IOException { //定义mabatis全局配置文件
        String resource = "SqlMapConfig.xml"; //加载mybatis全局配置文件 //InputStream inputStream = TestClient.class.getClassLoader().getResourceAsStream(resource);
 InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(inputStream); //根据sqlSessionFactory产生会话sqlsession
        session = factory.openSession();
    } //查询所有user表所有数据
 @Test public void testSelectAllUser() {
        String statement = "com.sl.mapper.ProductMapper.selectAllProduct";
        List<Product> listProduct =session.selectList(statement); for(Product product:listProduct)
        {
            System.out.println(product);
        } //关闭会话
 session.close();
    }

}

public class Product { private int Id; private String Name; private String Description; private BigDecimal UnitPrice; private String ImageUrl; private Boolean IsNew; public int getId() { return Id;
    } public void setId(int id) { this.Id = id;
    } public String getName() { return Name;
    } public void setName(String name) { this.Name = name;
    } public String getDescription() { return Description;
    } public void setDescription(String description) { this.Description = description;
    } public BigDecimal getUnitPrice() { return UnitPrice;
    } public void setUnitPrice(BigDecimal unitprice) { this.UnitPrice = unitprice;
    } public String getImageUrl() { return Name;
    } public void setImageUrl(String imageurl) { this.ImageUrl = imageurl;
    } public boolean getIsNew() { return IsNew;
    } public void setIsNew(boolean isnew) { this.IsNew = isnew;
    }

    @Override public String toString() { return "Product [id=" + Id + ", Name=" + Name + ", Description=" + Description + ", UnitPrice=" + UnitPrice + ", ImageUrl=" + ImageUrl + ", IsNew=" + IsNew+ "]";
    }
}