Question

我有时候会import java.util.Scanner; public class clock { public static void main(String[] args) throws InterruptedException { Scanner Input = new Scanner(System.in); System.out.print("HOUR: "); int hrs = Input.nextInt(); System.out.print("MIN: "); int min = Input.nextInt(); System.out.print("SEC: "); int sec = Input.nextInt(); while (true) { System.out.println(hrs + ":" + min + ":" + sec); sec = sec + 1; if (sec > 59) { sec = 0; min = min + 1; } if (min > 59) { min = 0; hrs = hrs + 1; } if (hrs > 12) { hrs = 1; } Thread.sleep (1000); } } }。看起来spring无法正确注入Caused by: java.lang.NullPointerException。我使用的是Spring 2.5.6并在WebSphere 7中部署。我们如何解决这个NPE问题？

org.springframework.jmx.export.notification.NotificationPublisher

Answer 1

将以下声明添加到我的spring上下文文件

后，错误消失了

<property name="notificationListeners">
            <list>
                <bean class="com.xyz.mbean.impl.XYZNotificationListenerBean">
                    <constructor-arg>
                        <ref bean="notificationListenerToDatabase" />
                    </constructor-arg>
                    <property name="namingStrategy" ref="mbeanNamingStrategy" />
                    <property name="mappedObjectNameTypePairs">
                        <map>
                            <entry>
                                <key>
                                    <value>sequenceGeneratorEarNotificationMBean</value>
                                </key>
                                <ref bean="NotificationMBean" />
                            </entry>
                        </map>
                    </property>
                </bean>
                <bean class="com.xyz.mbean.impl.XYZNotificationListenerBean">
                    <constructor-arg>
                        <ref bean="notificationListenerToTopic" />
                    </constructor-arg>
                    <property name="namingStrategy" ref="mbeanNamingStrategy" />
                    <property name="mappedObjectNameTypePairs">
                        <map>
                            <entry>
                                <key>
                                    <value>sequenceGeneratorEarNotificationMBean</value>
                                </key>
                                <ref bean="NotificationMBean" />
                            </entry>
                        </map>
                    </property>
                </bean>
                <bean class="com.xyz.mbean.impl.XYZNotificationListenerBean">
                    <constructor-arg ref="notificationListenerToExternal" />
                    <property name="namingStrategy" ref="mbeanNamingStrategy" />
                    <property name="mappedObjectNameTypePairs">
                        <map>
                            <entry key="sequenceGeneratorEarNotificationMBean" value-ref="NotificationMBean" />
                        </map>
                    </property>
                </bean>
            </list>
        </property>
    </bean>

Spring 2.5.6 JMX NotificationPublisher调用抛出NPE

1 个答案: