如何检查是否用Java建立了MongoDB连接？

Question

String mongoClientURI = "mongodb://" + DB_SRV_USR + ":" + DB_SRV_PWD + "@" + DB_URL + ":" + DB_PORT_CUS + "/" + dbName;
MongoClientURI connectionString = new MongoClientURI(mongoClientURI);

// enable SSL connection
MongoClientOptions.builder().sslEnabled(true).build();

if (this.mongoClient == null) {
    this.mongoClient = new MongoClient(connectionString);
}

// create database if doesn't exist
MongoDatabase mdb = this.mongoClient.getDatabase(dbName);

try {
    this.mongoClient.getAddress();
} catch (com.mongodb.MongoSocketOpenException e) {
    System.out.println("Switch to default port");
    /*…use default port logic…*/
}

问题是没有捕捉到此异常。尽管MongoDB引发以下异常：

com.mongodb.mongosocketOpenException：在com.mongodb.Connection.socketstream.open（socketstream.java:63)在com.mongodb.Connection.internalstreamConnection.open（internalstreamConnection.open（internalstreamConnection.java:114)在com.mongodb.Connection.defaultServerMonitor$servermonitorrunnable.run（defaultServerMonitor java.net.abstractplainsocketimpl.java:85)在java.net.abstractplainsocketimpl.doConnect（abstractplainsocketimpl.java:350)在java.net.abstractplainsocketimpl.connecttoAddress（abstractplainsocketimpl.java:206)在java.net.abstractplainsocketimpl.java:188)在java.net.abstractplainsocketimpl.connect（在com.mongodb.connection.socketstreamhelper.initialize(Socketstreamhelper.java:50)，com.mongodb.connection.socketstream.open(Socketstream.java:58)...3个以上

我的try-catch表达式无法捕获此异常。

我尝试了多种方法，例如捕捉：

• 异常
• RuntimeException
• MongosocketOpenException
• MongoException
• MongoCommandException

没有一个不起作用。

我的问题：

1. 如何检查MongoDB连接是否已建立？
2. 如何捕捉异常MongosocketOpenException？

Answer 1

>

我使用以下代码检查连接：

try {
    mongo.getAddress();
} catch (Exception e) {
    System.out.println("Database unavailable!");
    mongo.close();
    return;
}

我的猜测是this.mongoclient.getAddress()；不会抛出异常，但我并不知道

编辑：我通过以下方式初始化了它：

Builder builder = MongoClientOptions.builder().connectTimeout(3000);  
MongoClient mongo = new MongoClient(new ServerAddress("192.168.0.1", 3000), builder.build());