java - 具有多个数据源 Oracle 和 H2 的 Spring Boot

Question

我为我的角度项目开发了一个 spring boot RestController 并遇到了问题。在我的休息服务逻辑中，我使用了两个不同的数据库来获取数据。

在这里你可以看到数据源配置:

[应用程序属性]

#datasource1
spring.datasource.url=[url]
spring.datasource.username=[username]
spring.datasource.password=[password]
spring.datasource.driverClassName=org.h2.Driver

#datasource2
spring.secondDatasource.url=[url]
spring.secondDatasource.username=[username]
spring.secondDatasource.password=[password]
spring.secondDatasource.driverClassName=oracle.jdbc.OracleDriver

[数据源配置.java]

@Bean
@Primary
@ConfigurationProperties(prefix="spring.datasource")
public DataSource h2DataSource() {
    return DataSourceBuilder.create().build();
}

@Bean
@ConfigurationProperties(prefix="spring.secondDatasource")
public DataSource oracleDataSource() {
    return DataSourceBuilder.create().build();
}

日志输出:(没有针对此问题抛出异常)

...
2016-11-22 13:20:25.853 [INFO ] 1  [main] d.b.s.Application : Started Application in 7.757 seconds (JVM running for 12.515)
2016-11-22 13:20:31.731 [INFO ] 62 [http-nio-8080-exec-1] o.s.w.s.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization started
2016-11-22 13:20:31.757 [INFO ] 62 [http-nio-8080-exec-1] o.s.w.s.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 26 ms
2016-11-22 13:20:34.984 [INFO ] 65 [http-nio-8080-exec-5] d.b.s.r.RESTclient : /rest/getMyData
2016-11-22 13:20:34.992 [INFO ] 63 [http-nio-8080-exec-2] d.b.s.r.RESTclient : /rest/getMyData2
2016-11-22 13:20:34.993 [INFO ] 69 [http-nio-8080-exec-8] d.b.s.r.RESTclient : /rest/getMyData3
2016-11-22 13:20:35.004 [DEBUG] 65 [http-nio-8080-exec-5] d.b.s.DataSourceService : getH2Connection()
2016-11-22 13:20:35.022 [DEBUG] 63 [http-nio-8080-exec-2] d.b.s.DataSourceService : getOracleConnection()
2016-11-22 13:20:35.022 [DEBUG] 69 [http-nio-8080-exec-8] d.b.s.DataSourceService : getH2Connection()

问题是，rest-service 的每个使用的工作线程(http-nio-8080-?, ...)都在我的 DataSourceService 中的 datasource.getConnection() 处挂起。它永远卡住并等待无法获取的连接。

@Service
public class DataSourceService {
    private final DataSource h2DataSource;
    private final DataSource oracleDataSource;

    @Autowired
    public DataSourceService(DataSource h2DataSource, DataSource oracleDataSource) {
        this.h2DataSource = h2DataSource;
        this.oracleDataSource = oracleDataSource;
    }

    public Connection getH2Connection() throws SQLException {
        LoggerUtil.logDebug(getClass(), "getH2Connection()");
        return h2Connection.getConnection();
    }

    public Connection getOracleConnection() throws SQLException {
        LoggerUtil.logDebug(getClass(), "getOracleConnection()");
        return oracleConnection.getConnection();
    }
}

关于它的奇怪之处在于，有时它无需更改任何代码行(5% 的所有时间)就可以工作，而且大多数情况下(95% 的所有时间)它会挂起。

在我的 pom.xml 中，我有以下数据库驱动程序依赖项:

<dependency>
    <groupId>com.oracle</groupId>
    <artifactId>ojdbc6</artifactId>
    <version>11.2.0.4</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>1.4.193</version>
    <scope>runtime</scope>
</dependency>

如果所有数据源都有相同的驱动程序，这永远不会发生，但结合起来我发现了这种奇怪的行为。

我的想法是，只有在 oracle 之前初始化 h2Database 时才会发生这种情况。此时 spring 类加载器加载 h2-driver 类，它们将被缓存。接下来，oracle 被初始化，一些类将完全相同，因此一些 h2 类用于 oracle。因此，产生了奇怪的卡住状态。 (也许反之亦然)。

我现在的问题:为什么不能在Spring-boot中同时使用H2和Oracle数据库？

编辑:

经过一些调试，我发现了更多信息:

[org.apache.tomcat.jdbc.pool.ClassLoaderUtil]

Row 29:  loadClass(...)
...
Row 38: return Class.forName(className, true, cl);  //className: "oracle.jdbc.OracleDriver"  cl: Launcher$AppClassLoader

在 ClassLoaderUtil 中是按类名查找驱动程序类。类名“org.h2.Driver”可以毫无问题地解析，但“oracle.jdbc.OracleDriver”则不行。

之后我制作了一个线程转储，您可以在其中查看卡住的点。此时有5条卡死线，分别卡在不同位置。

http-nio-8080-exec-2@8307(可运行)(仅使用 oracle 数据库)

"http-nio-8080-exec-2@8307" daemon prio=5 tid=0x40 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
     blocks http-nio-8080-exec-6@8311
      at java.lang.Class.forName0(Class.java:-1)
      at java.lang.Class.forName(Class.java:348)
      at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
      at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
      at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
      at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
      at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
      - locked <0x2139> (a org.apache.tomcat.jdbc.pool.DataSource)
      at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
      at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
      at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)                        //<-- That's my package
      ...

http-nio-8080-exec-3@8308(可运行)(oracle和h2数据对比)

"http-nio-8080-exec-3@8308" daemon prio=5 tid=0x41 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
  at oracle.jdbc.driver.OracleDriver.<clinit>(OracleDriver.java:190)
  at java.lang.Class.forName0(Class.java:-1)
  at java.lang.Class.forName(Class.java:348)
  at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
  - locked <0x213d> (a org.apache.tomcat.jdbc.pool.DataSource)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
  at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)
  ...

http-nio-8080-exec-4@8309(可运行)(oracle和h2数据对比)

(与 exec-2 相同)

http-nio-8080-exec-5@8310(可运行)(仅使用 h2 数据库)

"http-nio-8080-exec-5@8310" daemon prio=5 tid=0x43 nid=NA runnable
   java.lang.Thread.State: RUNNABLE
  at sun.reflect.GeneratedConstructorAccessor109.newInstance(Unknown Source:-1)
  at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:-1)
  at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
  at java.lang.Class.newInstance(Class.java:442)
  at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380)
  at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404)
  at java.util.ServiceLoader$1.next(ServiceLoader.java:480)
  at java.sql.DriverManager$2.run(DriverManager.java:603)
  at java.sql.DriverManager$2.run(DriverManager.java:583)
  at java.security.AccessController.doPrivileged(AccessController.java:-1)
  at java.sql.DriverManager.loadInitialDrivers(DriverManager.java:583)
  at java.sql.DriverManager.<clinit>(DriverManager.java:101)
  at org.h2.Driver.load(Driver.java:155)
  at org.h2.Driver.<clinit>(Driver.java:41)
  at java.lang.Class.forName0(Class.java:-1)
  - locked <0x211b> (a java.lang.Class)
  at java.lang.Class.forName(Class.java:348)
  at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
  at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
  at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
  - locked <0x20e9> (a org.apache.tomcat.jdbc.pool.DataSource)
  at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)
  ...

http-nio-8080-exec-6@8311(等待监控入口)(oracle和h2数据对比)

"http-nio-8080-exec-6@8311" daemon prio=5 tid=0x44 nid=NA waiting for monitor entry
   java.lang.Thread.State: BLOCKED
 waiting for http-nio-8080-exec-2@8307 to release lock on <0x2139> (a org.apache.tomcat.jdbc.pool.DataSource)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
  at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131)
  at d.b.s.DataSourceService.getConnection(DataSourceService.java:51)
  ...

Answer 1

我遇到了和你一样的问题，但是在h2和mysql中。我没有同时使用h2和oracle，在这个post中，也许你能找到一些有用的东西。

这是我的双数据源配置:

maven 依赖:


<!-- stater mybatis -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>
<!-- jdbc -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>


```

datasource:
  km:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/km?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    max-active: 100
    max-idle: 10
    max-wait: 10000
    test-while-idle: true
  esb:
    driverClassName: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/esb?useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: root
    password: 123456
    max-active: 100
    max-idle: 10
    max-wait: 10000
    test-while-idle: true

```

数据源 km 配置类:```

import com.package.km.api.commons.config.datasource.annotation.UseDatasourceKM;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;
import java.lang.invoke.MethodHandles;
import java.sql.SQLException;

/**
 * km datasource config
 * Created by BeeNoisy on 16/5/23.
 */
@Configuration
@MapperScan(basePackages = "package.km", annotationClass = UseDatasourceKM.class, sqlSessionFactoryRef = KMDatasourceConfig.SQL_SESSION_FACTORY_NAME)
public class KMDatasourceConfig {
    public static final String SQL_SESSION_FACTORY_NAME = "sessionFactoryKm";
    public static final String TX_MANAGER = "txManagerKm";
    private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    @Bean(name = "datasourceKm")
    @Primary
    @ConfigurationProperties(prefix = "datasource.km")
    public DataSource dataSourceKm() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = TX_MANAGER)
    @Primary
    public PlatformTransactionManager txManagerKm() {
        return new DataSourceTransactionManager(dataSourceKm());
    }

    @Bean(name = KMDatasourceConfig.SQL_SESSION_FACTORY_NAME)
    @Primary
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {

        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setConfigLocation(new ClassPathResource("/mybatis/mybatis-conf.xml"));
        sqlSessionFactoryBean.setDataSource(dataSourceKm());
        return sqlSessionFactoryBean.getObject();
    }
}

```

这是数据源 esb 配置类:

```

import com.package.km.api.commons.condition.EsbEnabledCondition;
import com.package.km.api.commons.config.datasource.annotation.UseDatasourceESB;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;
import java.lang.invoke.MethodHandles;

/**
 * Created by BeeNoisy on 16/5/23.
 */
@Configuration
@Conditional(EsbEnabledCondition.class)
@MapperScan(basePackages = "package.esb", annotationClass = UseDatasourceESB.class, sqlSessionFactoryRef = EsbDatasourceConfig.SQL_SESSION_FACTORY_NAME)
public class EsbDatasourceConfig {
    public static final String SQL_SESSION_FACTORY_NAME = "sessionFactoryEsb";
    public static final String TX_MANAGER = "txManagerEsb";
    private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    @Bean(name = "datasourceEsb")
    @Conditional(EsbEnabledCondition.class)
    @ConfigurationProperties(prefix = "datasource.esb")
    public DataSource dataSourceEsb() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = TX_MANAGER)
    @Conditional(EsbEnabledCondition.class)
    public PlatformTransactionManager txManagerEsb() {
        return new DataSourceTransactionManager(dataSourceEsb());
    }

    @Bean(name = EsbDatasourceConfig.SQL_SESSION_FACTORY_NAME)
    @Conditional(EsbEnabledCondition.class)
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {

        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setConfigLocation(new ClassPathResource("/mybatis/mybatis-conf.xml"));
        sqlSessionFactoryBean.setDataSource(dataSourceEsb());
        return sqlSessionFactoryBean.getObject();
    }
}

```

然后您可以使用两个注释:UseDatasourceESB 或 UseDatasourceKM 来注释您的映射器类，例如:

```

@UseDatasourceKM
public interface GroupBaseDAO {
    public static final String COL_ALL = " id, name, create_time, last_update_time "; 
    public static final String TABLE = " group_base "; 

    @Select(" select " + COL_ALL + " from " + TABLE + " where id = #{id} ")
    public GroupBase findById(@Param("id") int id);

    @Select(" select " +
            COL_ALL +
            " from " +
            TABLE +
            " where id < #{lastId} " +
            " limit #{count} ")
    public List<GroupBase> list(
            @Param("lastId") int lastId,
            @Param("count") int count
    );
...

```

mysql\h2 和oracle 有两个数据源。顺便说一下，您可以在调试模型中运行您的代码，并进入 getConnection() 方法以查找更多详细信息。