在 org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1198) 處獲取 NullPointerException

Question

遷移自

    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.5</version>

到

    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.7</version>

在執行以下指令時

VelocityContext vc = getVelocityContext(valuesMap);
StringWriter writer = new StringWriter();
Velocity.evaluate(vc, writer, "[generate email processor - event id = " + event.getId() + "]", bodyTemplate);

我得到

java.lang.NullPointerException
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1198)
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1181)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1297)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1265)
        at org.apache.velocity.app.Velocity.evaluate(Velocity.java:180)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.generateMessage(GenerateMessageProcessor.java:1361)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.run(GenerateMessageProcessor.java:1155)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1198)
        at org.apache.velocity.runtime.RuntimeInstance.parse(RuntimeInstance.java:1181)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1297)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1265)
        at org.apache.velocity.app.Velocity.evaluate(Velocity.java:180)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.generateMessage(GenerateMessageProcessor.java:1361)
        at net.nationalpayment.core.backend.GenerateMessageProcessor$EventProcessor.run(GenerateMessageProcessor.java:1155)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)

我在應用程序執行期間初始化 RuntimeSingleton 一次，如下所示。

if(!RuntimeSingleton.isInitialized()) {
        RuntimeSingleton.init();
    }

為什么我得到 NullPointerException ？

Answer 1

在速度（版本 1.7）。 屬性已被外部化為名為velocity.property 的屬性文件。

根據我的要求指定下面提到的屬性后，所有其他屬性都使用默認值。問題得到解決。

runtime.log = /tmp/velocity.log