Java 当从方法a()调用方法b()时,新事务是否开始?
当从方法a调用方法b时,新事务是否开始? 或者这只是来自对象的方法调用,而注释不起作用? 如果是,如何启动该事务Java 当从方法a()调用方法b()时,新事务是否开始?,java,jakarta-ee,transactions,ejb,Java,Jakarta Ee,Transactions,Ejb,当从方法a调用方法b时,新事务是否开始? 或者这只是来自对象的方法调用,而注释不起作用? 如果是,如何启动该事务 @Stateless public class TestBean { @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED) public void a() { b(); } @TransactionAttribute(TransactionAttributeType
@Stateless
public class TestBean {
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public void a() {
b();
}
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public void b() {
}
}
不会启动任何事务。这被视为内部方法,并与当前事务关联。由于您需要一个方法声明NOT_SUPPORTED transaction属性,因此在调用方法a和b期间将不会创建任何事务。当客户端调用该方法时,事务属性是受尊重的,因此,如果某个组件将调用testBean.b,那么无论是否存在事务,都将创建新事务。不会启动任何事务。这被视为内部方法,并与当前事务关联。由于您需要一个方法声明NOT_SUPPORTED transaction属性,因此在调用方法a和b期间将不会创建任何事务。当客户端调用该方法时,事务属性是受尊重的,因此如果某个组件将调用testBean.b,则无论是否存在事务,都将创建新事务。您可以使用TransactionSynchronizationRegistry资源查询当前事务状态,轻松检查这一点。下面是我在Wildfly 8.1上尝试的一个示例: 1-将TransactionSynchronizationRegistry作为资源注入:
@Resource
TransactionSynchronizationRegistry txReg;
2-用于查询当前事务状态并返回可读字符串的小助手:
private String getTXStatus()
{
int txStatus = this.txReg.getTransactionStatus();
switch (txStatus)
{
case Status.STATUS_ACTIVE:
return "STATUS_ACTIVE";
case Status.STATUS_COMMITTED:
return "STATUS_COMMITTED";
case Status.STATUS_COMMITTING:
return "STATUS_COMMITTING";
case Status.STATUS_MARKED_ROLLBACK:
return "STATUS_MARKED_ROLLBACK";
case Status.STATUS_NO_TRANSACTION:
return "STATUS_NO_TRANSACTION";
case Status.STATUS_PREPARED:
return "STATUS_PREPARED";
case Status.STATUS_PREPARING:
return "STATUS_PREPARING";
case Status.STATUS_ROLLEDBACK:
return "STATUS_ROLLEDBACK";
case Status.STATUS_ROLLING_BACK:
return "STATUS_ROLLING_BACK";
case Status.STATUS_UNKNOWN:
return "STATUS_UNKNOWN";
default:
return "Unknown(" + txStatus + ")";
}
3-现在,您可以使用一些快速而肮脏的日志记录来指导您的业务方法,并且永远不要将System.out.println放入生产性EJB代码中
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public void a()
{
System.out.println("+++ a()");
System.out.println("TX status is " + getTXStatus());
b();
System.out.println("TX status is " + getTXStatus());
System.out.println("--- a()");
}
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public void b()
{
System.out.println("+++ b()");
System.out.println("TX status is " + getTXStatus());
System.out.println("--- b()");
}
4-现在我们可以从某个客户端调用a和b:
String beanName = "ejb:EJB3/MOD3//SagMalWas!de.treufuss.ejb3project.client.HelloWorldRemote";
HelloWorldBIF bif = HelloWorldBIF.class.cast(jndiContext.lookup(beanName));
bif.a();
bif.b();
这将在服务器控制台中生成以下输出:
12:58:33,123 INFO [stdout] (EJB default - 3) +++ a()
12:58:33,123 INFO [stdout] (EJB default - 3) TX status is STATUS_NO_TRANSACTION
12:58:33,123 INFO [stdout] (EJB default - 3) +++ b()
12:58:33,123 INFO [stdout] (EJB default - 3) TX status is STATUS_NO_TRANSACTION
12:58:33,123 INFO [stdout] (EJB default - 3) --- b()
12:58:33,124 INFO [stdout] (EJB default - 3) TX status is STATUS_NO_TRANSACTION
12:58:33,124 INFO [stdout] (EJB default - 3) --- a()
12:58:33,127 INFO [stdout] (EJB default - 4) +++ b()
12:58:33,128 INFO [stdout] (EJB default - 4) TX status is STATUS_ACTIVE
12:58:33,128 INFO [stdout] (EJB default - 4) --- b()
这证明从a调用b不会启动任何事务
附录
您可以通过从EJB上下文通过beans业务接口调用b方法来强制创建新事务。要做到这一点
1-将EJB上下文作为资源注入
@Resource
private SessionContext ctx;
2-通过业务接口调用b方法:
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public void a()
{
System.out.println("+++ a()");
System.out.println("TX status is " + getTXStatus());
// Direct invocation is treated as POJMC (plain old java method call
b();
// Indirect invocation via EJB context
HelloWorldLocal thisBean = ctx.getBusinessObject(HelloWorldLocal.class);
thisBean.b();
System.out.println("TX status is " + getTXStatus());
System.out.println("--- a()");
}
您可以通过使用TransactionSynchronizationRegistry资源查询当前事务状态来轻松检查。下面是我在Wildfly 8.1上尝试的一个示例: 1-将TransactionSynchronizationRegistry作为资源注入:
@Resource
TransactionSynchronizationRegistry txReg;
2-用于查询当前事务状态并返回可读字符串的小助手:
private String getTXStatus()
{
int txStatus = this.txReg.getTransactionStatus();
switch (txStatus)
{
case Status.STATUS_ACTIVE:
return "STATUS_ACTIVE";
case Status.STATUS_COMMITTED:
return "STATUS_COMMITTED";
case Status.STATUS_COMMITTING:
return "STATUS_COMMITTING";
case Status.STATUS_MARKED_ROLLBACK:
return "STATUS_MARKED_ROLLBACK";
case Status.STATUS_NO_TRANSACTION:
return "STATUS_NO_TRANSACTION";
case Status.STATUS_PREPARED:
return "STATUS_PREPARED";
case Status.STATUS_PREPARING:
return "STATUS_PREPARING";
case Status.STATUS_ROLLEDBACK:
return "STATUS_ROLLEDBACK";
case Status.STATUS_ROLLING_BACK:
return "STATUS_ROLLING_BACK";
case Status.STATUS_UNKNOWN:
return "STATUS_UNKNOWN";
default:
return "Unknown(" + txStatus + ")";
}
3-现在,您可以使用一些快速而肮脏的日志记录来指导您的业务方法,并且永远不要将System.out.println放入生产性EJB代码中
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public void a()
{
System.out.println("+++ a()");
System.out.println("TX status is " + getTXStatus());
b();
System.out.println("TX status is " + getTXStatus());
System.out.println("--- a()");
}
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public void b()
{
System.out.println("+++ b()");
System.out.println("TX status is " + getTXStatus());
System.out.println("--- b()");
}
4-现在我们可以从某个客户端调用a和b:
String beanName = "ejb:EJB3/MOD3//SagMalWas!de.treufuss.ejb3project.client.HelloWorldRemote";
HelloWorldBIF bif = HelloWorldBIF.class.cast(jndiContext.lookup(beanName));
bif.a();
bif.b();
这将在服务器控制台中生成以下输出:
12:58:33,123 INFO [stdout] (EJB default - 3) +++ a()
12:58:33,123 INFO [stdout] (EJB default - 3) TX status is STATUS_NO_TRANSACTION
12:58:33,123 INFO [stdout] (EJB default - 3) +++ b()
12:58:33,123 INFO [stdout] (EJB default - 3) TX status is STATUS_NO_TRANSACTION
12:58:33,123 INFO [stdout] (EJB default - 3) --- b()
12:58:33,124 INFO [stdout] (EJB default - 3) TX status is STATUS_NO_TRANSACTION
12:58:33,124 INFO [stdout] (EJB default - 3) --- a()
12:58:33,127 INFO [stdout] (EJB default - 4) +++ b()
12:58:33,128 INFO [stdout] (EJB default - 4) TX status is STATUS_ACTIVE
12:58:33,128 INFO [stdout] (EJB default - 4) --- b()
这证明从a调用b不会启动任何事务
附录
您可以通过从EJB上下文通过beans业务接口调用b方法来强制创建新事务。要做到这一点
1-将EJB上下文作为资源注入
@Resource
private SessionContext ctx;
2-通过业务接口调用b方法:
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public void a()
{
System.out.println("+++ a()");
System.out.println("TX status is " + getTXStatus());
// Direct invocation is treated as POJMC (plain old java method call
b();
// Indirect invocation via EJB context
HelloWorldLocal thisBean = ctx.getBusinessObject(HelloWorldLocal.class);
thisBean.b();
System.out.println("TX status is " + getTXStatus());
System.out.println("--- a()");
}
这取决于您使用的库/框架。平面java当然不是。它的可能复制取决于您使用的库/框架。当然,在平面java中是不可能的