myBatis系列之一：搭建开发环境

淩亂°似流年 2022-04-11 06:22 242阅读 0赞

一.工程结构

![ade433f5-01c3-33c1-a85b-7b81de79fffd.png][]

二.在类路径下创建mybatis的配置文件Configuration.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>
    	<typeAliases>
    		<typeAlias alias="User" type="com.bijian.study.model.User" />
    	</typeAliases>
    	
    	<environments default="development">
    	  <environment id="development">
    		<transactionManager type="JDBC"/>
    		<dataSource type="POOLED">
    			<property name="driver" value="com.mysql.jdbc.Driver" />
    			<property name="url" value="jdbc:mysql://10.60.222.65:3306/test" />
    			<property name="username" value="test" />
    			<property name="password" value="test" />
    		</dataSource>
    	  </environment>
    	</environments>
    	
    	<mappers>
    		<mapper resource="com/bijian/study/model/User.xml" />
    	</mappers>
    </configuration>

三.执行创建数据库和表的sql

-- Create the database named 'hbatis'.
    -- It's OK to use `, not OK to use ' or " surrounding the database name to prevent it from being interpreted as a keyword if possible.
    CREATE DATABASE IF NOT EXISTS `hbatis`
    DEFAULT CHARACTER SET = `UTF8`;
    
    -- Create a table named 'User'
    CREATE TABLE `user` (
    	`id` int(11) NOT NULL AUTO_INCREMENT,
    	`name` varchar(50) DEFAULT NULL,
    	`age` int(11) DEFAULT NULL,
    	`address` varchar(200) DEFAULT NULL,
    	PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
    
    -- Insert a test record
    Insert INTO `user` VALUES ('1', 'bijian', '120', 'hangzhou,westlake');
    
    -- drop table
    drop table `user`;

四.User类

package com.bijian.study.model;
    
    public class User {
        
        private int id;
        private String name;
        private int age;
        private String address;
        
        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 int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    
        public String getAddress() {
            return address;
        }
    
        public void setAddress(String address) {
            this.address = address;
        }
    
        // 如果有带参数的构造器，编译器不会自动生成无参构造器。当查询需要返回对象时，ORM框架用反射来调用对象的无参构造函数，导致异常：java.lang.NoSuchMethodException: com.bijian.study.model.User.<init>()
        // 这时需要明确写出：
        public User() {
        }
    
        public User(int id, String address) {
            this.id = id;
            this.address = address;
        }
    
        public User(String name, int age, String address) {
            this.name = name;
            this.age = age;
            this.address = address;
        }
    }

User.java对应的User.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">
    <mapper namespace="com.bijian.study.model.UserMapper">
    	<select id="getUserById" parameterType="int" resultType="User">
    		select * from `user` where id = #{id}
    	</select>
    </mapper>

五.测试类

package com.bijian.study.test;
    
    import java.io.IOException;
    import java.io.Reader;
    
    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 org.junit.BeforeClass;
    import org.junit.Test;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import com.bijian.study.model.User;
    
    public class MyBatisBasicTest {
    
        private static final Logger log = LoggerFactory.getLogger(MyBatisBasicTest.class);
        private static SqlSessionFactory sqlSessionFactory;
    
        private static Reader reader;
    
        @BeforeClass
        public static void initial() {
            try {
                reader = Resources.getResourceAsReader("Configuration.xml");
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
            } catch (IOException e) {
                log.error("Error thrown while reading the configuration: {}", e);
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        log.error("Error thrown while closing the reader: {}", e);
                    }
                }
            }
        }
    
        @Test
        public void queryTest() {
            SqlSession session = sqlSessionFactory.openSession();
            User user = (User) session.selectOne("com.bijian.study.model.UserMapper.getUserById", 1);
            log.info("{}: {}", user.getName(), user.getAddress());
        }
    }

运行单元测试结果：

00:28:18.710 [main] INFO  com.bijian.study.test.MyBatisBasicTest - bijian: hangzhou,westlake

文章来源：[http://czj4451.iteye.com/blog/1976365][http_czj4451.iteye.com_blog_1976365]

[ade433f5-01c3-33c1-a85b-7b81de79fffd.png]: /images/20220411/1ae52a600eb14eaba78b229aa187b4d5.png
[http_czj4451.iteye.com_blog_1976365]: http://czj4451.iteye.com/blog/1976365