动态数据源路由 - 未初始化DataSource路由器 [英] Dynamic datasource routing - DataSource router not initialized

问题描述

我指的是文章，我们可以使用Spring Framework中的AbstractRoutingDataSource动态更改应用程序使用的数据源。我正在使用Mybatis（3.3.0）和Spring（4.1.6.RELEASE）。如果从主数据库获取数据时发生异常，我想切换到备份数据库。在这个例子中，我使用了hsql和mysql db。

I'm referring to this article, in which we can use the AbstractRoutingDataSource from Spring Framework to dynamically change the data source used by the application. I'm using Mybatis (3.3.0) with Spring (4.1.6.RELEASE). I want to switch to the backup database if exception occurs while getting data from main db. In this example, i have used hsql and mysql db.

RoutingDataSource ：

public class RoutingDataSource extends AbstractRoutingDataSource {

@Override
protected Object determineCurrentLookupKey() {
    return DataSourceContextHolder.getTargetDataSource();
 }
}

DataSourceContextHolder ：

public class DataSourceContextHolder {

private static final ThreadLocal<DataSourceEnum> contextHolder = new ThreadLocal<DataSourceEnum>();

public static void setTargetDataSource(DataSourceEnum targetDataSource) {
    contextHolder.set(targetDataSource);
}

public static DataSourceEnum getTargetDataSource() {
    return (DataSourceEnum) contextHolder.get();
}

public static void resetDefaultDataSource() {
    contextHolder.remove();
 }
}

ApplicationDataConfig ：

@Configuration
@MapperScan(basePackages = "com.sample.mapper")
@ComponentScan("com.sample.config")
@PropertySource(value = {"classpath:app.properties"},
                ignoreResourceNotFound = true)
public class ApplicationDataConfig {

@Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
    PropertySourcesPlaceholderConfigurer configurer =
        new PropertySourcesPlaceholderConfigurer();
    return configurer;
}

@Bean
public SqlSessionFactoryBean sqlSessionFactoryBean() throws Exception {
    SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
    RoutingDataSource routingDataSource = new RoutingDataSource();
    routingDataSource.setDefaultTargetDataSource(dataSource1());
    Map<Object, Object> targetDataSource = new HashMap<Object, Object>();
    targetDataSource.put(DataSourceEnum.HSQL, dataSource1());
    targetDataSource.put(DataSourceEnum.BACKUP, dataSource2());
    routingDataSource.setTargetDataSources(targetDataSource);
    sessionFactory.setDataSource(routingDataSource);
    sessionFactory.setTypeAliasesPackage("com.sample.common.domain");

    sessionFactory.setMapperLocations(
        new PathMatchingResourcePatternResolver()
            .getResources("classpath*:com/sample/mapper/**/*.xml"));

    return sessionFactory;
}

@Bean
public DataSource dataSource1() {
    return new EmbeddedDatabaseBuilder().setType(EmbeddedDatabaseType.HSQL).addScript(
            "classpath:database/app-hsqldb-schema.sql").addScript(
            "classpath:database/app-hsqldb-datascript.sql").build();
}


@Bean
public DataSource dataSource2() {
    PooledDataSourceFactory pooledDataSourceFactory = new PooledDataSourceFactory();
    pooledDataSourceFactory.setProperties(jdbcProperties());
    return pooledDataSourceFactory.getDataSource();
}

@Bean
protected Properties jdbcProperties() {
    //Get the data from properties file
    Properties jdbcProperties = new Properties();
    jdbcProperties.setProperty("url", datasourceUrl);
    jdbcProperties.setProperty("driver", datasourceDriver);
    jdbcProperties.setProperty("username", datasourceUsername);
    jdbcProperties.setProperty("password", datasourcePassword);
    jdbcProperties.setProperty("poolMaximumIdleConnections", maxConnectionPoolSize);
    jdbcProperties.setProperty("poolMaximumActiveConnections", minConnectionPoolSize);

    return jdbcProperties;
}
}

客户：

 @Autowired
 private ApplicationMapper appMapper;

public MyObject getObjectById(String Id) {
    MyObject myObj = null;
    try{
        DataSourceContextHolder.setTargetDataSource(DataSourceEnum.HSQL);
        myObj = appMapper.getObjectById(Id);
    }catch(Throwable e){
        DataSourceContextHolder.setTargetDataSource(DataSourceEnum.BACKUP);
        myObj = appMapper.getObjectById(Id);  
    }finally{
        DataSourceContextHolder.resetDefaultDataSource();
    }
    return getObjectDetails(myObj);
}

我收到以下异常

### Error querying database.  Cause: java.lang.IllegalArgumentException: DataSource router not initialized

但是我能够让工作正常如果我一次只使用一个数据库，这意味着数据源配置没有问题。

However i'm able to get things working if i'm using only one db at a time, this means there is no issue with data source configuration.

推荐答案

你能来吗？尝试最后一行（按相同顺序）： -

Can you try this last line once (in same order) :-

targetDataSource.put(DataSourceEnum.HSQL, dataSource1());
targetDataSource.put(DataSourceEnum.BACKUP, dataSource2());
routingDataSource.setTargetDataSources(targetDataSource);

routingDataSource.afterPropertiesSet();

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