Question

我想将问题扩展到问题的另一个问题：Cannot convert object of type to JMS message. Supported message payloads are: String, byte array, Map<String,?>, Serializable object

我收到以下错误

java.lang.ClassCastException: java.util.HashMap cannot be cast to com.jms.testing.spring.InstructionMessage
    at com.jms.testing.spring.SpringJmsInstructionMessageConsumer.receiveMessage(SpringJmsInstructionMessageConsumer.java:20)
    at com.jms.testing.spring.InstructionMessageTest.testActriveMQMessages(InstructionMessageTest.java:43)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

appContextWithMessageConverter.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jms="http://www.springframework.org/schema/jms"
    xsi:schemaLocation="http://www.springframework.org/schema/jms http://www.springframework.org/schema/jms/spring-jms.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="classpath:jms.properties" />

    <bean id="jmsConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
        <property name="brokerURL" value="${jms.brokerURL}" />
    </bean>

    <bean id="pooledJmsConnectionFactory" class="org.apache.activemq.pool.PooledConnectionFactory" destroy-method="stop">
        <property name="connectionFactory" ref="jmsConnectionFactory" />
        <property name="maxConnections" value="50" />
    </bean>

    <jms:listener-container container-type="default" connection-factory="pooledJmsConnectionFactory" acknowledge="auto" >
        <!-- <jms:listener destination="messageDestination" ref="messageDestination" /> -->
        <jms:listener destination="messageDestination" ref="myListener" />
    </jms:listener-container>

    <bean id="instructionMessageConverter" class="com.jms.testing.spring.InstructionMessageConverter" />

    <bean id="myListener" class="com.jms.testing.spring.MyListener" />

    <bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate">
        <constructor-arg ref="pooledJmsConnectionFactory" />
        <property name="defaultDestination" ref="messageDestination" />
        <property name="receiveTimeout" value="${jms.receiveTimeout}" />
        <!-- <property name="messageConverter" ref="instructionMessageConverter" /> -->

    </bean>

    <bean id="springJmsInstProducer" class="com.jms.testing.spring.SpringJmsInstructionMessageProducer">
        <property name="jmsTemplate" ref="jmsTemplate" />
    </bean>

    <bean id="springJmsInstConsumer" class="com.jms.testing.spring.SpringJmsInstructionMessageConsumer">
        <property name="jmsTemplate" ref="jmsTemplate" />
    </bean> 

    <bean id="messageDestination" class="org.apache.activemq.command.ActiveMQQueue">
        <constructor-arg value="messageQueue1" />
    </bean>
</beans>

SpringJmsInstructionMessageConsumer.java

public class SpringJmsInstructionMessageConsumer {

    private JmsTemplate jmsTemplate;

    public JmsTemplate getJmsTemplate() {
        return jmsTemplate;
    }

    public void setJmsTemplate(JmsTemplate jmsTemplate) {
        this.jmsTemplate = jmsTemplate;
    }

    public InstructionMessage receiveMessage() throws JMSException {
        InstructionMessage instructionMessage = (InstructionMessage) getJmsTemplate().receiveAndConvert(); //line-20, its breaking here
        return instructionMessage;  
    }
}

在第20行，代码违反上述代码

@Test
    public void test() throws JMSException{
        InstructionMessage m1 = new InstructionMessage(10,10,10,10,10);
        System.out.println("Sending person " + m1);
        springJmsProducer.sendMessage(m1);

        InstructionMessage m2 = new InstructionMessage(5,5,5,5,5);
        System.out.println("Sending person " + m2);
        springJmsProducer.sendMessage(m2);

        InstructionMessage m3 = new InstructionMessage(0,0,0,0,0);
        System.out.println("Sending person " + m3);
        springJmsProducer.sendMessage(m3);

        System.out.println("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~");


        System.out.println("Consumer receives " + springJmsConsumer.receiveMessage());
    }

Answer 1

如上所述，由于使用默认的1L，只需添加生成的串行版本ID！

public class InstructionMessage implements Serializable{

private static final long serialVersionUID = -295422703255886286L;

java.lang.ClassCastException：java.util.HashMap无法强制转换为com.jms.testing.spring.InstructionMessage

1 个答案: