springboot基于注解动态配置多数据源以及多数据源的事务统一
标签:java,多数据源
一、动态注入多数据源
1、配置多数据源配置文件（application-db.properties）
######多数据源配置文件####################
###第一个####spring.datasource.first.name=firstspring.datasource.first.url=jdbc:oracle:thin:@127.0.0.1:1521:orcl
spring.datasource.first.username=sepcore
spring.datasource.first.password=sepcore
spring.datasource.first.driverClassName=oracle.jdbc.driver.OracleDriver
spring.datasource.first.mapperLocations=classpath:mappers/*Mapper.xml
####第二个####spring.datasource.second.name=secondspring.datasource.second.url=jdbc:mysql://127.0.0.1:3306/test?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
spring.datasource.second.username=root
spring.datasource.second.password=123456
spring.datasource.second.driverClassName=com.mysql.jdbc.Driver
spring.datasource.second.mapperLocations=classpath:mappers/*Mapper.xml
#####mapper接口所在包#######
scanner.mapperInterfacePackage=com.example.demo.mappers
2、读取配置文件类（DataSourceConfig）
public class DataSourceConfig { /**
* 存储dataSource、SqlSessionTemplate、DataSourceTransactionManager */
private Map>mapMap; /**
* 获取mybatis扫描的指定接口包（所有数据源的接口放在同一的父包下面） */
private String mapperInterfacePackage; public DataSourceConfig(){
mapMap = new HashMap<>();
InputStream in = DataSourceConfig.class.getClassLoader().
getResourceAsStream("application-db.properties");
Properties properties = new Properties(); try {
properties.load(in);
} catch (IOException e) {
e.printStackTrace();
}
Set set = properties.stringPropertyNames(); for (String s : set) { //判断是否是mapper接口指定包路径
if (s.contains("mapperInterfacePackage")){
mapperInterfacePackage = properties.get(s).toString(); continue;
}
String key = s.substring(0, s.lastIndexOf(".")); if (mapMap.containsKey(key)){
Map map = mapMap.get(key);
map.put(s,properties.get(s));
}else{
Mapmap = new HashMap<>();
map.put(s,properties.get(s));
mapMap.put(key,map);
}
}
} public String getMapperInterfacePackage() { return mapperInterfacePackage;
} /**
* 获取SqlSessionTemplate
* @return
* @throws Exception */
public MapgetSqlSessionTemplateAndDataSource() throws Exception {
Set>> entries = this.mapMap.entrySet();
Mapresult = new HashMap<>(entries.size()); for (Map.Entry> entry : entries) {
String key = entry.getKey();
Map map = entry.getValue();
DataSource dataSource = DataSourceBuilder.create().url(map.get(key+".url").toString()).
username(map.get(key+".username").toString()).password(map.get(key+".password").toString()).
driverClassName(map.get(key+".driverClassName").toString()).
build(); //为每个数据源设置事务
DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
dataSourceTransactionManager.setDataSource(dataSource);
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean(); //设置dataSource数据源 sqlSessionFactoryBean.setDataSource(dataSource); //设置*mapper.xml路径
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(map.get(key+".mapperLocations").toString()));
String s = map.get(key + ".name").toString();
result.put(s+"SqlSessionTemplate",new SqlSessionTemplate(sqlSessionFactoryBean.getObject()));
result.put(s+"DataSource",dataSource);
result.put(s+"DataSourceTransactionManager",dataSourceTransactionManager);
} return result;
}
}
3、使用注解（DataSourceRoute），确定每个mapper接口使用哪个数据源
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)public @interface DataSourceRoute {
String name() default "first";
}
@DataSourceRoutepublic interface SepUserMapper {
List> findByUserLevel(Long userLevel); void insert(Mapmap);
}
@DataSourceRoute(name = "second")public interface IDiDataItemMapper {
@Select("SELECT dataitem_id,name FROM di_dataitem WHERE dataitem_id=#{dataItemId}")
MapselectOne(Long dataItemId); void insert(Map map);
}
4、扫描指定包下面的mapper接口
public class ClassScanner { public static Map>getMapperInterface(String mapperInterfacePackage) throws Exception {
Map>classMap = new HashMap<>();
ClassLoader loader = Thread.currentThread().getContextClassLoader(); //将"."替换成"/"
String packagePath = mapperInterfacePackage.replace(".", "/");
URL url = loader.getResource(packagePath);
List fileNames = null; if (url != null) {
String type = url.getProtocol(); if ("file".equals(type)) {
fileNames = getClassNameByFile(url.getPath(), null, true);
}
} for (String classPath : fileNames) {
classMap.putAll(getClassByPath(classPath));
} return classMap;
} /**
* 读取package下的所有类文件
* @param filePath
* @param className
* @param childPackage
* @return
*/
private static List getClassNameByFile(String filePath, List className, boolean childPackage) {
List myClassName = new ArrayList<>();
File file = new File(filePath);
File[] childFiles = file.listFiles(); for (File childFile : childFiles) { if (childFile.isDirectory()) { if (childPackage) {
myClassName.addAll(getClassNameByFile(childFile.getPath(), myClassName, childPackage));
}
} else {
String childFilePath = childFile.getPath(); if (childFilePath.endsWith(".class")) {
childFilePath = childFilePath.substring(childFilePath.indexOf("\\classes") + 9,
childFilePath.lastIndexOf("."));
childFilePath = childFilePath.replace("\\", ".");
myClassName.add(childFilePath);
}
}
} return myClassName;
} /**
* 将Mapper的标准文件，转成 Mapper Class
* @param classPath
* @return
* @throws Exception */
private static Map> getClassByPath(String classPath) throws Exception{
ClassLoader loader = Thread.currentThread().getContextClassLoader();
Map> classMap = new HashMap<>();
classMap.put(getClassAlias(classPath),loader.loadClass(getFullClassName(classPath))); return classMap;
} /**
* 将Mapper的标准文件，转成java标准的类名称
* @param classPath
* @return
* @throws Exception */
private static String getFullClassName(String classPath) throws Exception{ int comIndex = classPath.indexOf("com");
classPath = classPath.substring(comIndex);
classPath = classPath.replaceAll("\\/", "."); return classPath;
} /**
* 根据类地址，获取类的Alais，即根据名称，按照驼峰规则，生成可作为变量的名称
* @param classPath
* @return
* @throws Exception */
private static String getClassAlias(String classPath) throws Exception{
String split = "\\/";
String[] classTmp = classPath.split(split);
String className = classTmp[classTmp.length-1]; return toLowerFisrtChar(className);
} /**
* 将字符串的第一个字母转小写
* @param className
* @return
*/
private static String toLowerFisrtChar(String className){
String fisrtChar = className.substring(0,1);
fisrtChar = fisrtChar.toLowerCase(); return fisrtChar+className.substring(1);
}
5、使用BeanFactoryPostProcessor动态插入数据源
@Componentpublic class DataSourceBean implements BeanFactoryPostProcessor{
@Override public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
System.out.println("在spring处理bean前，将自定义的bean注册到容器中======================"); DataSourceConfig dataSourceConfig = new DataSourceConfig(); try {
Map sqlSessionTemplateAndDataSource = dataSourceConfig.getSqlSessionTemplateAndDataSource();
Map> mapperInterface = ClassScanner.getMapperInterface(dataSourceConfig.getMapperInterfacePackage());
Set>> entries = mapperInterface.entrySet(); for (Map.Entry> entry : entries) {
MapperFactoryBean mapperFactoryBean = new MapperFactoryBean();
Class value = entry.getValue();
DataSourceRoute dataSourceRoute = value.getAnnotation(DataSourceRoute.class); if (null==dataSourceConfig){ continue;
}
String name = dataSourceRoute.name();
SqlSessionTemplate template = (SqlSessionTemplate) sqlSessionTemplateAndDataSource.get(name + "SqlSessionTemplate");
mapperFactoryBean.setMapperInterface(value);
mapperFactoryBean.setSqlSessionTemplate(template);
mapperFactoryBean.afterPropertiesSet();
configurableListableBeanFactory.registerSingleton(name+"MapperFactory",mapperFactoryBean.getObject());
configurableListableBeanFactory.registerSingleton(name+"DataSource",sqlSessionTemplateAndDataSource.get(name + "DataSource"));
configurableListableBeanFactory.registerSingleton(name+"SqlSessionTemplate",template);
configurableListableBeanFactory.registerSingleton(name+"DataSourceTransactionManager",sqlSessionTemplateAndDataSource.get(name+"DataSourceTransactionManager"));
}
} catch (Exception e) {
System.err.println(e.getMessage());
}
}
}
至此多数据源动态加载就完成了。
二、多数据源统一事务控制
当使用多数据源时，单一的事务会出现问题（当在service层同时操作两个数据源时，当发生异常，只会回滚离抛出异常最近的数据源的数据）
1、自定义事务注解
@Target({ElementType.METHOD,ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)public @interface CustomTransaction {
String[] name() default {"firstDataSourceTransactionManager"};
}2、创建aop切面进行事务控制
@Component
@Aspectpublic class TransactionAop {
@Pointcut(value = "@annotation(com.example.demo.annon.CustomTransaction)") public void pointCut(){}
@Around(value = "pointCut()&&@annotation(annotation)") public Object twiceAsOld(ProceedingJoinPoint point, CustomTransaction annotation) throws Throwable {
Stack dataSourceTransactionManagerStack = new Stack();
Stack transactionStatuStack = new Stack(); try { if (!openTransaction(dataSourceTransactionManagerStack, transactionStatuStack, annotation)) { return null;
}
Object ret = point.proceed();
commit(dataSourceTransactionManagerStack, transactionStatuStack); return ret;
} catch (Throwable e) {
rollback(dataSourceTransactionManagerStack, transactionStatuStack); throw e;
}
} /**
* 开启事务处理方法
*
* @param dataSourceTransactionManagerStack
* @param transactionStatuStack
* @param multiTransactional
* @return
*/
private boolean openTransaction(Stack dataSourceTransactionManagerStack,
Stack transactionStatuStack, CustomTransaction multiTransactional) {
String[] transactionMangerNames = multiTransactional.name(); if (ArrayUtils.isEmpty(multiTransactional.name())) { return false;
} for (String beanName : transactionMangerNames) { //根据事务名称获取具体的事务
DataSourceTransactionManager dataSourceTransactionManager = (DataSourceTransactionManager) SpringContextUtil
.getBean(beanName);
TransactionStatus transactionStatus = dataSourceTransactionManager
.getTransaction(new DefaultTransactionDefinition());
transactionStatuStack.push(transactionStatus);
dataSourceTransactionManagerStack.push(dataSourceTransactionManager);
} return true;
} /**
* 提交处理方法
*
* @param dataSourceTransactionManagerStack
* @param transactionStatuStack */
private void commit(Stack dataSourceTransactionManagerStack,
Stack transactionStatuStack) { while (!dataSourceTransactionManagerStack.isEmpty()) {
dataSourceTransactionManagerStack.pop().commit(transactionStatuStack.pop());
}
} /**
* 回滚处理方法
*
* @param dataSourceTransactionManagerStack
* @param transactionStatuStack */
private void rollback(Stack dataSourceTransactionManagerStack,
Stack transactionStatuStack) { while (!dataSourceTransactionManagerStack.isEmpty()) {
dataSourceTransactionManagerStack.pop().rollback(transactionStatuStack.pop());
}
}
}
3、在service层指定使用哪个事务
//注意事务的命名规则
@CustomTransaction(name = {"firstDataSourceTransactionManager","secondDataSourceTransactionManager"}) public void setSepUserMapper(){ //操作数据源2
Mapmm = new HashMap<>(2);
mm.put("dataitemId",1L);
mm.put("name","测试");
diDataItemMapper.insert(mm); //操作数据源1
Mapmap = new HashMap<>(3);
map.put("userId",1L);
map.put("userName","张三");
map.put("name","平台管理员");
sepUserMapper.insert(map); throw new RuntimeException("sfsa");
}
辅助类：SpringContextUtil
@Componentpublic class SpringContextUtil implements ApplicationContextAware{ private static ApplicationContext applicationContext;
@Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
SpringContextUtil.applicationContext = applicationContext;
} /**
* @Description: 获取spring容器中的bean,通过bean名称获取
* @param beanName bean名称
* @return: Object 返回Object,需要做强制类型转换
* @author: zongf
* @time: 2018-12-26 10:45:07 */
public static Object getBean(String beanName){ return applicationContext.getBean(beanName);
} /**
* @Description: 获取spring容器中的bean, 通过bean类型获取
* @param beanClass bean 类型
* @return: T 返回指定类型的bean实例
* @author: zongf
* @time: 2018-12-26 10:46:31 */
public static T getBean(Class beanClass) { return applicationContext.getBean(beanClass);
} /**
* @Description: 获取spring容器中的bean, 通过bean名称和bean类型精确获取
* @param beanName bean 名称
* @param beanClass bean 类型
* @return: T 返回指定类型的bean实例
* @author: zongf
* @time: 2018-12-26 10:47:45 */
public static T getBean(String beanName, Class beanClass){ return applicationContext.getBean(beanName,beanClass);
}