SpringBoot學習記錄(三)——整合Mybatis
以前整合了Spring+SpringMVC+Mybatis,今天用SpringBoot整合了Mybatis,發現這個比之前的SSM的整合方便的太多,省去大量的配置檔案,也許是我還沒用到很深入吧,話不多說,直接進入正題。
1、建立一個SpringBoot專案:
2、下一步:
3、然後加入一些需要的依賴,這裡用的SpringBoot2:
4、建立成功之後檢視一下pom裡面的配置:
<?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> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.1.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.thr</groupId> <artifactId>spring-boot-mybatis</artifactId> <version>0.0.1-SNAPSHOT</version> <name>spring-boot-mybatis</name> <description>Demo project for Spring Boot</description> <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-jdbc</artifactId> </dependency> <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>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> <!-- mybatis generator 自動生成程式碼外掛 --> <plugin> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator-maven-plugin</artifactId> <version>1.3.2</version> <configuration> <configurationFile>${basedir}/src/main/resources/generatorConfig.xml</configurationFile> <overwrite>true</overwrite> <verbose>true</verbose> </configuration> </plugin> </plugins> </build> </project>
注意:pom檔案裡面的 mybatis generator 自動生成程式碼外掛 是自己要加進去的:
<!-- mybatis generator 自動生成程式碼外掛 --> <plugin> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator-maven-plugin</artifactId> <version>1.3.2</version> <configuration> <configurationFile>${basedir}/src/main/resources/generatorConfig.xml</configurationFile> <overwrite>true</overwrite> <verbose>true</verbose> </configuration> </plugin>
5、配置application.properties檔案,一般不使用這個,推薦使用application.yml,將properties改成yml就可以了,但是這裡方便就不該了。
server.port=8080 #mapper檔案的位置 mybatis.mapper-locations=classpath:mapper/*.xml #對應實體類的位置 type-aliases-package=com.thr.entity #配置資料來源 spring.datasource.username=root spring.datasource.password=root #使用druid資料來源 #type: com.alibaba.druid.pool.DruidDataSource spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.url=jdbc:mysql://127.0.0.1:3306/db_user?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8
6、然後建立資料庫db_user:
CREATE TABLE `t_user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(64) DEFAULT NULL,
`password` varchar(64) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of t_user
-- ----------------------------
INSERT INTO `t_user` VALUES ('1', 'admin', '123');
7、使用Mybatis的Generator自動生成類,在專案的resources下新增generatorConfig.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
<!-- 資料庫驅動:選擇你的本地硬碟上面的資料庫驅動包-->
<classPathEntry location="E:\mysql-connector-java-5.1.28-bin.jar"/>
<context id="testTables" targetRuntime="MyBatis3">
<commentGenerator>
<!-- 是否去除自動生成的註釋 true:是 : false:否 -->
<property name="suppressAllComments" value="true" />
</commentGenerator>
<!--資料庫連線的資訊:驅動類、連線地址、使用者名稱、密碼 -->
<jdbcConnection driverClass="com.mysql.jdbc.Driver"
connectionURL="jdbc:mysql://localhost:3306/db_user"
userId="root"
password="root">
</jdbcConnection>
<!-- <jdbcConnection driverClass="oracle.jdbc.OracleDriver"
connectionURL="jdbc:oracle:thin:@127.0.0.1:1521:user"
userId="yycg"
password="yycg">
</jdbcConnection> -->
<!-- 預設false,把JDBC DECIMAL 和 NUMERIC 型別解析為 Integer,為 true時把JDBC DECIMAL 和
NUMERIC 型別解析為java.math.BigDecimal -->
<javaTypeResolver>
<property name="forceBigDecimals" value="false" />
</javaTypeResolver>
<!-- targetProject:生成PO類的位置 -->
<javaModelGenerator targetPackage="com.thr.entity"
targetProject=".\src\main\java">
<!-- enableSubPackages:是否讓schema作為包的字尾 -->
<property name="enableSubPackages" value="false" />
<!-- 從資料庫返回的值被清理前後的空格 -->
<property name="trimStrings" value="true" />
</javaModelGenerator>
<!-- targetProject:mapper對映檔案生成的位置 -->
<sqlMapGenerator targetPackage="mapper"
targetProject=".\src\main\resources">
<!-- enableSubPackages:是否讓schema作為包的字尾 -->
<property name="enableSubPackages" value="false" />
</sqlMapGenerator>
<!-- targetPackage:mapper介面生成的位置 -->
<javaClientGenerator type="XMLMAPPER"
targetPackage="com.thr.dao"
targetProject=".\src\main\java">
<!-- enableSubPackages:是否讓schema作為包的字尾 -->
<property name="enableSubPackages" value="false" />
</javaClientGenerator>
<!-- 指定資料庫表 tableName是資料庫中的表名或檢視名 domainObjectName是實體類名-->
<table tableName="t_user"
domainObjectName="User"
enableCountByExample="false"
enableUpdateByExample="false"
enableDeleteByExample="false"
enableSelectByExample="false"
selectByExampleQueryId="false">
</table>
<!-- 有些表的欄位需要指定java型別
<table schema="" tableName="">
<columnOverride column="" javaType="" />
</table> -->
</context>
</generatorConfiguration>
8、然後在IDEA的右邊找到Maven Projects,找到之前的外掛,雙擊:注意!!!同一張表一定不要執行多次,因為mapper的對映檔案中會生成多次的程式碼,切記不要多次執行!!!
執行完成後就可以看到:
9、開啟類SpringbootMybatisDemoApplication.java,這個是springboot的啟動類。我們需要新增點東西:
注意:@MapperScan("com.thr.dao")這個註解非常的關鍵,這個對應了專案中mapper(dao)所對應的包路徑,很多同學就是這裡忘了加導致異常的。如果不在啟動類這裡加,也可以在Mapper類上面添加註解@Mapper
,建議使用上面那種,不然每個mapper加個註解也挺麻煩的。
package com.thr;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.thr.dao")
public class SpringBootMybatisApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootMybatisApplication.class, args);
}
}
10、然後就是Controller,Service層了:
UserController類:
@RestController
public class UserController {
@Autowired
private UserService userService;
@GetMapping(value = "/user")
public Object User(){
return userService.findAllUser();
}
}
UserMapper下要加一個方法List<User> findAllUser():
public interface UserMapper {
int deleteByPrimaryKey(Integer id);
int insert(User record);
int insertSelective(User record);
User selectByPrimaryKey(Integer id);
int updateByPrimaryKeySelective(User record);
int updateByPrimaryKey(User record);
List<User> findAllUser();
}
所以相應的Mapper.xml也要新增一條SQL語句;
<select id="findAllUser" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
select
<include refid="Base_Column_List" />
from t_user
</select>
UserService介面:
/**
* @author
* @name
*/
public interface UserService {
List<User> findAllUser();
}
UserServiceImpl實現類:
/**
* @author
* @name
*/
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
public List<User> findAllUser() {
return userMapper.findAllUser();
}
}
總體目錄結構如下:
11、執行啟動類,然後訪問http://localhost:8080/user:
成功訪問,SpringBoot成功整合Mybatis。
如果訪問不了,那就在pom下面的build中新增下面的程式碼:這是IDEA的原因,有時候有些檔案沒有編譯到target下,配置下面這個後就可以了。
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
<resource>
<directory>src/main/webapp</directory>
<targetPath>META-INF/resources</targetPath>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>