Spring Boot 菜鸟教程 3 MyBatis

MyBatis

MyBatis 本是apache的一个开源项目iBatis, 2010年这个项目由apache 迁移到了google code，并且改名为MyBatis 。2013年11月迁移到Github。

• 集成spring boot 的时候必须在mapper接口上面标注@Mapper注解

项目图片

这里写图片描述

pom.xml

-只需要在pom.xml引入需要的数据库配置，就会自动访问此数据库，如果需要配置其他数据库，可以在application.properties进行添加
-默认使用org.apache.tomcat.jdbc.pool.DataSource创建连接池

<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.jege.spring.boot</groupId>
    <artifactId>spring-boot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-mybatis</name>
    <url>http://maven.apache.org</url>

    <!-- 公共spring-boot配置，下面依赖jar文件不用在写版本号 -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.1.RELEASE</version>
        <relativePath />
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <!-- 持久层 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>

        <!-- h2内存数据库 -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

    <build>
        <finalName>spring-boot-mybatis</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

模型对象User

package com.jege.spring.boot.mybatis.entity;

/**
 * @author JE哥
 * @email 1272434821@qq.com
 * @description:模型对象
 */
public class User {
  private Long id;
  private String name;
  private Integer age;

  public User() {
  }

  public User(String name, Integer age) {
    this.name = name;
    this.age = age;
  }
}

持久层UserMapper

package com.jege.spring.boot.mybatis.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

import com.jege.spring.boot.mybatis.entity.User;

/**
 * @author JE哥
 * @email 1272434821@qq.com
 * @description:持久层接口，由spring自动生成其实现
 */
@Mapper
public interface UserMapper {
  @Delete("drop table t_user if exists")
  void dropTable();

  @Insert("create table t_user (id bigint generated by default as identity, age integer, name varchar(255), primary key (id))")
  void createTable();

  @Insert("insert into t_user(name,age) values(#{name},#{age})")
  void insert(User user);

  @Select("select id,name,age from t_user")
  List<User> findAll();

  @Select("select id,name,age from t_user where name like #{name}")
  List<User> findByNameLike(String name);

  @Delete("delete from t_user")
  void deleteAll();

}

不需要application.properties

测试类UserMapperTest

package com.jege.spring.boot.mybatis;

import static org.assertj.core.api.Assertions.assertThat;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.jege.spring.boot.mybatis.entity.User;
import com.jege.spring.boot.mybatis.mapper.UserMapper;

/**
 * @author JE哥
 * @email 1272434821@qq.com
 * @description:
 */
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest()
public class UserMapperTest {
  @Autowired
  UserMapper userMapper;

  // 每次执行Test之前先删除表，创建表
  @Before
  public void before() throws Exception {
    userMapper.dropTable();
    userMapper.createTable();
  }

  // 打印出class com.sun.proxy.$Proxy66表示spring注入通过jdk动态代理获取接口的子类
  @Test
  public void proxy() throws Exception {
    System.out.println(userMapper.getClass());
  }

  @Test
  public void save() throws Exception {
    for (int i = 0; i < 10; i++) {
      User user = new User("jege" + i, 25 + i);
      userMapper.insert(user);
    }
  }

  @Test
  public void all() throws Exception {
    save();
    assertThat(userMapper.findAll()).hasSize(10);
  }

  @Test
  public void findByName() throws Exception {
    save();
    assertThat(userMapper.findByNameLike("jege%")).hasSize(10);
  }

  // 每次执行Test之后清空数据
  @After
  public void destroy() throws Exception {
    userMapper.deleteAll();
  }

}

源码地址

https://github.com/je-ge/spring-boot

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