文章出處

問題描述

報如下錯誤，很顯然，問題原因：空指針異常；

ERROR (localhost-startStop-1) [   ] o.a.s.h.d.s.SolrDataImportProperties Error loading DataImportScheduler properties
java.lang.NullPointerException
        at sun.nio.fs.UnixPath.normalizeAndCheck(UnixPath.java:77)
        at sun.nio.fs.UnixPath.<init>(UnixPath.java:71)
        at sun.nio.fs.UnixFileSystem.getPath(UnixFileSystem.java:281)
        at java.nio.file.Paths.get(Paths.java:84)
        at org.apache.solr.core.SolrResourceLoader.<init>(SolrResourceLoader.java:151)
        at org.apache.solr.handler.dataimport.scheduler.SolrDataImportProperties.loadProperties(SolrDataImportProperties.java:36)
        at org.apache.solr.handler.dataimport.scheduler.BaseTimerTask.reloadParams(BaseTimerTask.java:57)
        at org.apache.solr.handler.dataimport.scheduler.BaseTimerTask.<init>(BaseTimerTask.java:39)
        at org.apache.solr.handler.dataimport.scheduler.DeltaImportHTTPPostScheduler.<init>(DeltaImportHTTPPostScheduler.java:20)
        at org.apache.solr.handler.dataimport.scheduler.ApplicationListener.contextInitialized(ApplicationListener.java:47)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4716)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5178)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:152)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:724)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:700)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
        at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1107)
        at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1841)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)

詳細原因：定時更新使用的jar包apache-solr-dataimportscheduler-1.1.jar是網上找的，好像版本更不上了，反編譯一下，問題出在SolrDataImportProperties類的36行，如下標紅位置：

    public void loadProperties(boolean force) {
        try {
            SolrResourceLoader loader = new SolrResourceLoader(null);
            logger.info("Instance dir = " + loader.getInstanceDir());

            String configDir = loader.getConfigDir();
            configDir = SolrResourceLoader.normalizeDir(configDir);

我的solr版本是5.5.3，找到org.apache.solr.core.SolrResourceLoader，查看其構造方法，有四個，我們使用的是public SolrResourceLoader(Path instanceDir)，由于傳入的instanceDir為null報錯（具體內部代碼就沒調試進去了）：

  public SolrResourceLoader() {
    this(locateSolrHome(), null, null);
  }

  public SolrResourceLoader(Path instanceDir, ClassLoader parent)
  {
    this(instanceDir, parent, null);
  }

  public SolrResourceLoader(Path instanceDir) {
    this(instanceDir, null, null);
  }

  public SolrResourceLoader(Path instanceDir, ClassLoader parent, Properties coreProperties)
  {
    if (instanceDir == null) {
　　...