JAVAWEB--Mybatis02

Maven项目导入依赖

<?xml version="1.0" encoding="UTF-8"?>
<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>cn.ronghuanet</groupId>
    <artifactId>mybatis-day02</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
    	<!-- mybatis核心包 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.1</version>
        </dependency>
        <!-- mysql驱动包 -->
        <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>
             <version>5.1.26</version>
         </dependency>
         <!-- junit测试包 -->
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.12</version>
             <scope>test</scope>
         </dependency>
        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
  </dependencies>
    <!-- 局部jdk 1.8配置，pom.xml中 -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Mybatis集成

Mybatis配置文件

logo4j.properties

#\u5168\u5C40\u65E5\u5FD7\u914D\u7F6E
log4j.rootLogger = info,console

#log level: 
#debug is used by develop,  error or warn is used by online
log4j.logger.com.ronghuanet=debug


### \u914D\u7F6E\u8F93\u51FA\u5230\u63A7\u5236\u53F0
log4j.appender.console = org.apache.log4j.ConsoleAppender
### \u4F7F\u7528System.out\u6253\u5370\u65E5\u5FD7
log4j.appender.console.Target = System.out
### \u6307\u5B9A\u65E5\u5FD7\u7684\u683C\u5F0F\u5E03\u5C40(\u65E5\u5FD7\u662F\u6709\u683C\u5F0F\u7684)
log4j.appender.console.layout = org.apache.log4j.PatternLayout
### \u65E5\u5FD7\u7684\u6253\u5370\u683C\u5F0F
log4j.appender.console.layout.ConversionPattern =  %d{ABSOLUTE} %5p %c{1}:%L - %m%n

jdbcproperties

jdbc.username=root
jdbc.password=admin
jdbc.url=jdbc:mysql:///mybatis
jdbc.driverClassName=com.mysql.jdbc.Driver

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">
<configuration>
   <!-- 加载jdbc.properties-->
    <properties resource="jdbc.properties"/>
    <!--申明操作数据库的环境-->
    <environments default="MYSQL">
        <environment id="MYSQL">
            <!--使用jdbc的事务-->
            <transactionManager type="JDBC"/>
            <!--支持连接池-->
            <dataSource type="POOLED">
                <!--自动补全结构：ctrl+shift+回车-->
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="driver" value="${jdbc.driverClassName}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
       <!-- 加载mapper.xml文件-->
    </mappers>
</configuration>

创建Mybatis工具类并测试

public class MybatisUtils {
    private static SqlSessionFactory sessionFactory ;
    static{
        try {
            //提示处理异常快捷键    alt+回车       移动代码的快捷键  alt+上键或者下键
            //快速使用变量接收，    alt+回车
            InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
            //根据io流创建SqlSessionFactory对象
            sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static SqlSession openSession(){
        if (sessionFactory != null) {
            return sessionFactory.openSession();
        }
        return null;
    }
}

测试代码

public class MybatisTest {

    @Test
    public void test() throws Exception{
        SqlSession sqlSession = MybatisUtils.openSession();
        System.out.println(sqlSession);
        MybatisUtils.closeSession(sqlSession);

    }
}

创建模型

public class Product {
    private Long id;
    private String name;
    private BigDecimal price;
    /**
     * alt+insert:快速生成setter  getter方法  toString方法   构造方法
     */
	//getter，setter代码略...
}

productMapper接口

public interface ProductMapper {
    Product findOne(Long id);
}

创建对应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">
<!--注：namespace的内容就是ProductMapper接口的全限定名-->
<mapper namespace="org.test..mybatis._01_batch.mapper.ProductMapper">
    <!--id的值保证ProductMapper接口的方法名一值-->
    <select id="findOne" parameterType="long" resultType="org.test.mybatis._01_batch.domain.Product">
        select * from product where id = #{id}
    </select>
</mapper>

注册mapper.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">
<configuration>
     ...
    <mappers>
       <!-- 加载mapper.xml文件-->
        <mapper resource="org/test/mybatis/_01_batch/mapper/ProductMapper.xml" />
    </mappers>
</configuration>

获取单个对象

public class MyBatisTest {
    /**
     * 定义一个映射器mapper接口，使用mybatis自动为我们创建代理类
     * @throws Exception
     */
    @Test
    public void findOne()throws Exception{
        //获取到会话对象
        SqlSession session = MybatisUtils.openSession();
        //拿到映射对象，可以做相应的操作
        ProductMapper mapper = session.getMapper(ProductMapper.class);
        Product product = mapper.findOne(1L);

        System.out.println(product);
    }
}

本篇主要写了IDEA如何集成Mybatis，后续还会介绍mybatis映射等知识。笔者小，中，大厂均有面试经历，坚持每日分享java全栈知识，希望和大家共同进步。