SpringBoot整合MyBatis(註解版+XML配置版)
阿新 • • 發佈：2018-12-17
一.公共部分
1.建立SpringBoot專案，加入依賴
<?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>com.peng.demo</groupId> <artifactId>springboot-mybatis</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>springboot-mybatis</name> <description>springboot-mybatis</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.6.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.12</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
注:這裡使用阿里巴巴的druid資料庫連線池，也可以不使用。
2.建立資料庫就資料表
CREATE TABLE `tb_user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(50) DEFAULT NULL, `password` varchar(50) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 CREATE TABLE `tb_address` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(100) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8
注:簡單建立springboot資料庫，在其中建立tb_user資料表
3.建立實體
public class TbUser { private Integer id; private String username; private String password; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public String toString() { return "TbUser [id=" + id + ", username=" + username + ", password=" + password + "]"; } }
public class TbAddress {
private Integer id;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "TbAddress [id=" + id + ", name=" + name + "]";
}
}4.配置資料庫
在application.properties檔案中加入
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.jdbc.Driver5.配置資料來源（不使用druid資料來源的可以跳過此步）
在application.properties檔案中指定使用的資料來源，及配置資料來源
spring.datasource.type=com.alibaba.druid.pool.DruidDataSou
spring.datasource.maxActive=20
spring.datasource.initialSize=5
spring.datasource.minIdle=5
spring.datasource.maxWait=60000
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.minEvictableIdleTimeMillis=300000
import javax.sql.DataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.alibaba.druid.pool.DruidDataSource;
@Configuration
public class DruidConfig {
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource druidDataSource() {
return new DruidDataSource();
}
}注:這裡配置druid資料來源，指定將properties檔案中以spring.datasource開頭的配置對映到DruidDataSource的屬性中
二.通過註解方式配置MyBatis
1.書寫Mapper介面
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import com.peng.demo.pojo.TbUser;
@Mapper
public interface TbUserMapper {
@Select("select * from tb_user where id=#{id}")
TbUser findBuyId(Integer id);
}注:在類的頭上加上@Mapper註解。
2.測試
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.SpringRunner;
import com.peng.demo.mapper.TbUserMapper;
import com.peng.demo.pojo.TbUser;
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootMybatisApplicationTests {
@Autowired
private TbUserMapper tbUserMapper;
@Test
public void contextLoads() {
TbUser tbUser = tbUserMapper.findBuyId(1);
System.out.println(tbUser);
}
}測試結果
問題一：如果專案中存在大量mapper介面，每個mapper介面上都加@Mapper註解會很麻煩，SpringBoot提供在主類上加上@MapperScan("com.peng.demo.mapper")的掃描包形式配置mapper，現在去掉TbUserMapper上的註解，測試依舊成功。
問題二：如果將tbUser中的欄位username改為userName，tb_user表中的欄位username改為user_name查詢會出現啥問題呢？
會看到，userName為null，SpringBoot整合MyBatis預設無法識別駝峰命名法，那麼如何實現駝峰命名法呢？
import org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyBatisConfig {
@Bean
public ConfigurationCustomizer configurationCustomizer(){
return new ConfigurationCustomizer(){
@Override
public void customize(org.apache.ibatis.session.Configuration configuration) {
//開啟駝峰命名法
configuration.setMapUnderscoreToCamelCase(true);
}
};
}
}配置MyBatis，開啟駝峰命名法，測試就成功啦。
三：通過XML檔案配置MyBatis
1.建立mapper介面
import com.peng.demo.pojo.TbAddress;
public interface TbAddressMapper {
int insert(TbAddress tbAddress);
}
2.在resource資料夾下建立MyBatis資料夾，並在其下建立mybatis-config.xml主配置檔案
<?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>
<settings>
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>
</configuration>注：其中mapUnderscoreToCamelCase表示開啟駝峰命名法
3.在MyBatis資料夾下建立mapper資料夾，在其下建立TbAddressMapper.xml檔案
<?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.peng.demo.mapper.TbAddressMapper">
<insert id="insert">
INSERT INTO tb_address(name) VALUES (#{name})
</insert>
</mapper>
4.在application.properties檔案中配置MyBatis配置檔案地址
mybatis.config-location=classpath:MyBatis/mybatis-config.xml
mybatis.mapper-locations=classpath:MyBatis/mapper/*.xml5.測試
@Autowired
private TbAddressMapper tbAddressMapper;
@Test
public void test2() {
TbAddress tbAddress = new TbAddress();
tbAddress.setName("杭州");
int insert = tbAddressMapper.insert(tbAddress);
System.out.println(insert);
}
新增成功。
至此，SpringBoot簡單整合MyBatis就已經完了，技術一般，如有錯誤，請留言更正。