Spring Boot Mybatis简单使用
Spring Boot Mybatis简单使用
步骤说明
- build.gradle：依赖添加
- application.properties：配置添加
- 代码编写
- 测试
build.gradle：依赖添加
需要添加下面三个依赖：
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
implementation 'org.mybatis.spring.boot:mybatis-spring-boot-starter:2.1.0'
implementation 'mysql:mysql-connector-java'
}
application.properties：配置添加
配置文件的编写需要注意参数的配置，比如SSL那个一般要设置为false，driver-class-name也要注意一下，不要写错了，文件的大致内容如下：
mybatis.type-aliases-package=com.seckill.spring.mapper
spring.datasource.url=jdbc:mysql://10.33.8.189:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
代码编写
在入口函数添加Mapper扫描配置，这样不必在每个Mapper上加上Mapper注解，大致如下：
package com.seckill.spring;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.seckill.spring.mapper")
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
编辑商品实体类，大致如下：
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.validation.constraints.Size;
@Entity
public class Goods {
public Goods(int id, String name, int amount) {
this.id = id;
this.name = name;
this.amount = amount;
}
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;
@Size(min = 1, max = 50)
private String name;
private int amount;
}
编写Mapper接口类，大致内容如下：
import com.seckill.spring.entity.Goods;
import org.apache.ibatis.annotations.*;
import java.util.List;
public interface GoodsMapper {
@Insert("INSERT INTO goods(name, amount) VALUES('${name}', #{amount})")
Integer insertGoods(@Param("name")String name, @Param("amount")Integer amount) throws Exception;
@Select("SELECT * FROM goods")
List<Goods> findAll();
@Select("SELECT * FROM goods WHERE id = #{id}")
Goods findById(@Param("id") Integer id);
@Update("UPDATE goods SET amount = #{goods.amount} WHERE id = #{goods.id}")
Integer updateGoods(@Param("goods") Goods goods) throws Exception;
@Delete("Delete FROM goods")
Integer deleteAll();
}
其中要注意的是$和#的用法，前者用于字符串变量，后者用于整型变量
// This example creates a prepared statement, something like select * from teacher where name = ?;
@Select("Select * from teacher where name = #{name}")
Teacher selectTeachForGivenName(@Param("name") String name);
// This example creates n inlined statement, something like select * from teacher where name = 'someName';
@Select("Select * from teacher where name = '${name}'")
Teacher selectTeachForGivenName(@Param("name") String name);
测试
测试还有些坑，不如类上面的注解应该如代码中的那样才有用，并且有时发现不了测试函数，需要去掉@Test注解，再重新添加后运行。大致打代码如下：
import com.seckill.spring.Application;
import com.seckill.spring.entity.Goods;
import com.seckill.spring.mapper.GoodsMapper;
import org.junit.Assert;
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.annotation.DirtiesContext;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import java.util.List;
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(
classes = Application.class,
webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT
)
@DirtiesContext
public class GoodsMapperTest {
@Autowired
private GoodsMapper goodsMapper;
@Test
public void testAll() throws Exception {
goodsMapper.deleteAll();
Assert.assertEquals(0, goodsMapper.findAll().size());
Integer response = goodsMapper.insertGoods("good1", 1000);
Assert.assertEquals(1, response.intValue());
List<Goods> goods = goodsMapper.findAll();
Assert.assertEquals(1, goods.size());
int id = goods.get(0).getId();
Assert.assertNotNull(goodsMapper.findById(id));
Goods newGoods = new Goods(id, "good1", 100);
Assert.assertEquals(1, goodsMapper.updateGoods(newGoods).intValue());
Assert.assertEquals(100, goodsMapper.findById(id).getAmount());
}
}
