如何自定义 SpringBoot 多数据源的 starter 组件
SpringForAll
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本案例我们使用多数据源封装成一个starter组件，以方便使用多数据源访问数据库的操作
创建一个普通Java项目，引入SpringBoot相关的依赖
pom.xml
<?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 https://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>2.6.3</version>
<relativePath/>
</parent>
<groupId>com.gitee.kenewstar.multi.datasource</groupId>
<artifactId>multi-datasource-spring-boot-starter</artifactId>
<version>0.0.1</version>
<name>multi-datasource-spring-boot-starter</name>
<description>multi-datasource-spring-boot-starter</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
</dependencies>
</project>
创建常量类和注解
public interface Const {
String DEFAULT = "default";
String MULTI_DS = "multiDataSource";
String CONFIG_PREFIX = "spring.datasource.multi";
}
数据源注解
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
String value() default Const.DEFAULT;
}
创建多数据源属性类
主要用于存储SpringBoot配置文件中配置的数据源属性
@Component
@ConfigurationProperties(prefix = Const.CONFIG_PREFIX)
public class MultiDataSourceProperties {
private Map<String, DataSourceProp> dataSourcePropMap;
public Map<String, DataSourceProp> getDataSourcePropMap() {
return dataSourcePropMap;
}
public void setDataSourcePropMap(Map<String, DataSourceProp> dataSourcePropMap) {
this.dataSourcePropMap = dataSourcePropMap;
}
}
public class DataSourceProp extends HashMap<String, String> {
}
创建数据源key的切换工具
主要用于设置当前线程下数据源切换时的数据源唯一标识key，以便获取指定的数据源
public class DynamicDataSourceHolder {
private static final ThreadLocal<String> DATA_SOURCE_THEAD_LOCAL =
ThreadLocal.withInitial(() -> Const.DEFAULT);
public static String getDataSource() {
return DATA_SOURCE_THEAD_LOCAL.get();
}
public static void setDataSource(String dataSource) {
DATA_SOURCE_THEAD_LOCAL.set(dataSource);
}
public static void remove() {
DATA_SOURCE_THEAD_LOCAL.remove();
}
}
创建多数据源类
创建多数据源类继承AbstractRoutingDataSource类，重写determineCurrentLookupKey()方法，用于获取当前线程中的指定的数据源key，通过该key拿到对应的数据源对象
public class MultiDataSource extends AbstractRoutingDataSource {
private static final Logger LOGGER = Logger.getLogger(MultiDataSource.class.getName());
@Override
protected Object determineCurrentLookupKey() {
String key = DynamicDataSourceHolder.getDataSource();
LOGGER.info("DataSource key ---> " + key);
return key;
}
}
创建多数据源的切面类
切面类主要用于获取被数据与注解指定的方法，拿到其注解中的属性值，再设置到数据源key设置组件中，方便数据源类获取该key
需使用@Order设置切面优先级，否则设置无效
@Aspect
@Order(100)
public class DynamicDataSourceAdviser {
@Pointcut("@annotation(com.gitee.kenewstar.multi.datasource.common.DataSource)")
public void pointcut(){};
@Around("pointcut()")
public Object around(ProceedingJoinPoint point) throws Throwable {
try {
MethodSignature methodSignature = (MethodSignature) point.getSignature();
//获取被代理的方法对象
Method targetMethod = methodSignature.getMethod();
// 获取数据源注解
DataSource ds = targetMethod.getAnnotation(DataSource.class);
if (Objects.nonNull(ds)) {
DynamicDataSourceHolder.setDataSource(ds.value());
}
return point.proceed();
} finally {
DynamicDataSourceHolder.remove();
}
}
}
创建数据源配置类
@Configuration
@EnableConfigurationProperties(MultiDataSourceProperties.class)
public class MultiDataSourceConfig {
public static final String DS_TYPE = "dsType";
@Resource
private MultiDataSourceProperties multiDataSourceProperties;
private DataSource createDs(DataSourceProp dsProp) {
DataSource dataSource = null;
try {
Class<?> dsClass = Class.forName(dsProp.get(DS_TYPE));
if (DataSource.class.isAssignableFrom(dsClass)) {
dataSource = (DataSource) dsClass.getConstructor().newInstance();
DataSource finalDataSource = dataSource;
ReflectionUtils.doWithFields(dsClass, field -> {
field.setAccessible(true);
field.set(finalDataSource, dsProp.get(field.getName()));
}, field -> {
if (Objects.equals(dsProp.get(DS_TYPE), field.getName())) {
return false;
}
return Objects.nonNull(dsProp.get(field.getName()));
});
}
} catch (Exception e) {
throw new RuntimeException(e);
}
return dataSource;
}
@Bean(Const.MULTI_DS)
@Primary
public DataSource multiDataSource() {
MultiDataSource multiDataSource = new MultiDataSource();
Map<Object, Object> dataSourceMap = new HashMap<>(multiDataSourceProperties.getDataSourcePropMap().size());
Map<String, DataSourceProp> dataSourcePropMap = multiDataSourceProperties.getDataSourcePropMap();
dataSourcePropMap.forEach((lookupKey,dsProp) -> {
dataSourceMap.put(lookupKey, createDs(dsProp));
});
multiDataSource.setTargetDataSources(dataSourceMap);
multiDataSource.setDefaultTargetDataSource(dataSourceMap.get(Const.DEFAULT));
return multiDataSource;
}
@Bean
public DataSourceTransactionManager dataSourceTransactionManager(
@Qualifier(Const.MULTI_DS) DataSource multiDataSource) {
DataSourceTransactionManager tx = new DataSourceTransactionManager();
tx.setDataSource(multiDataSource);
return tx;
}
@Bean
public DynamicDataSourceAdviser dynamicDataSourceAdviser() {
return new DynamicDataSourceAdviser();
}
}
配置spring.factories文件
在resources目录下创建META-INF目录，在该目录创建spring.factories
文件内容如下：
设置key为开启自动配置的注解全路径名，后面的value值为配置类全路径名，本starter组件中为数据源配置类，如有多个配置类，则以逗号分隔，以反斜杆表示忽略换行
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.gitee.kenewstar.multi.datasource.config.MultiDataSourceConfig
这样我们封装的一个简单的多数据源starter组件就完成了，只需进行maven打包即可在本地使用
maven命令：mvn clean install
使用示例
引入打包后的依赖
<dependency>
<groupId>com.gitee.kenewstar.multi.datasource</groupId>
<artifactId>multi-datasource-spring-boot-starter</artifactId>
<version>0.0.1</version>
</dependency>
修改SpringBoot全局配置文件
default为默认数据源，必须配置， master为可选数据源，名称可自定义。
数据源的属性名称为对应的dsType数据源类型的属性字段
spring:
datasource:
multi:
data-source-prop-map:
default:
dsType: com.zaxxer.hikari.HikariDataSource
jdbcUrl: jdbc:mysql://localhost:3306/test
username: root
password: kenewstar
master:
dsType: com.zaxxer.hikari.HikariDataSource
jdbcUrl: jdbc:mysql://localhost:3306/test2
username: root
password: kenewstar
使用数据源
直接在指定的方法上添加@DataSource注解即可，注解的默认值为default,数据源的切换通过注解的值进行切换。值为application.yml中配置的default，master等
@Service
public class PersonService {
@Resource
private PersonMapper personMapper;
@DataSource("master")
@Transactional(rollbackFor = Exception.class)
public void insertPerson() {
personMapper.insert(new Person(null, "kk", 12));
personMapper.insert(new Person(null, "kk", 12));
}
}
@Service
public class PersonService {
@Resource
private PersonMapper personMapper;
@DataSource("master")
@Transactional(rollbackFor = Exception.class)
public void insertPerson() {
personMapper.insert(new Person(null, "kk", 12));
personMapper.insert(new Person(null, "kk", 12));
}
}
多数据源starter组件源码地址：
https://gitee.com/kenewstar/multi-datasource-spring-boot-starter
感谢阅读，希望对你有所帮助 :)
来源：blog.csdn.net/weixin_45840947/article/details/123892165
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