我正在尝试从部署在 JBOSS 中的应用程序写入 mongodb，这就是我得到的结果，我需要在 mongodb 中做些什么吗？从论坛的讨论来看，这似乎是一个并发问题。

14:00:07,083 WARNING [com.mongodb.tcp] (Camel (camel-2) thread #3 - JmsConsumer[barTopic]) Exception executing isMaster command on /127.0.0.1:27017: java.lang.NullPointerException
        at com.mongodb.DBPort._open(DBPort.java:203) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBPort.go(DBPort.java:107) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBPort.go(DBPort.java:88) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBPort.findOne(DBPort.java:143) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBPort.runCommand(DBPort.java:148) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBTCPConnector.initDirectConnection(DBTCPConnector.java:539) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.Mongo.getMaxBsonObjectSize(Mongo.java:600) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBApiLayer$MyCollection.insert(DBApiLayer.java:233) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBApiLayer$MyCollection.insert(DBApiLayer.java:205) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBCollection.insert(DBCollection.java:57) [mongo-java-driver-2.9.1.jar:]
        at com.mongodb.DBCollection.insert(DBCollection.java:100) [mongo-java-driver-2.9.1.jar:]
        at com.magick.magicktrader.BarServiceBean.addBarToMongoDB(BarServiceBean.java:196) [magicktrader.jar:0.6.0-SNAPSHOT]
        at com.magick.magicktrader.BarServiceBean.getBar(BarServiceBean.java:40) [magicktrader.jar:0.6.0-SNAPSHOT]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.6.0_10]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [rt.jar:1.6.0_10]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [rt.jar:1.6.0_10]
        at java.lang.reflect.Method.invoke(Method.java:597) [rt.jar:1.6.0_10]

方法调用

    MongoURI uri = null;
        uri = new MongoURI("mongodb://localhost:27017");

        try{
    mongo = new Mongo(uri);
    } catch (NumberFormatException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (UnknownHostException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}       
    //prop.getProperty("database")
    db = mongo.getDB("charts");
    db.requestStart();
    //prop.getProperty("collection")
    dbCollection = db.getCollection("bars");


    /**
     * Bar Structure - attributes
     * 
     * symbol,low,high
     * open,close,time
     * volume;
     **/
    for (Bar bar : barList) {
        document = new BasicDBObject();
        document.put("symbol", bar.getSymbol());
        document.put("low", bar.getLow());
        document.put("high", bar.getHigh());
        document.put("open", bar.getOpen());
        document.put("close", bar.getClose());
        document.put("time", bar.getTime());
        document.put("volume", bar.getVolume());
        //dbCollection.insert(document);
        //prop.getProperty("collection").trim()
        dbCollection.getCollection("bars");
        dbCollection.save(document, WriteConcern.NORMAL);
    }

最佳答案

1>这可能是不同连接的问题，我遇到了同样的问题，因为“我多次调用同一个连接类”。我通过使连接类成为单例来修复它。我使用 MongoClient 类进行连接。所以我会用文字解释一下，第一次只为mongoDb获取一个连接，从第二次开始使用相同的连接。 我也是 Mongos 的新手，希望这有效。

关于java - 在 mongodb 中执行 isMaster 命令时出现异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12933273/