如何用java驱动程序查询mongodb

Question

我想使用java驱动程序查询MongoDB数据库。
例如，这些是 mycoll 集合的两个文档：

{
"_id":"4d85c7039ab0fd70a117d73100",
"person_id":"100", 
"name":"UFlQsAWmgp",
"surname":"ohJTiGRqsM",
"place":"UtXVBKoajo",
"age":90
}
{
"_id":"4d85c7039ab0fd70a117d73101",
"person_id":"101", 
"name":"AosStuizVj",
"surname":"BCYcWKDTdu",
"place":"jRlEszdLOw",
"age":62
}

现在我想使用Java驱动程序检索所有5岁的人：

try
        { 
            MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
            String database = "test";
            MongoDatabase db = mongoClient.getDatabase(database);
            System.out.println("*****Connect to database successfully*****");
            String collection="mycoll";
            MongoCollection coll = db.getCollection(collection);
            System.out.println("*****Connect to collection " + "\"" + collection + "\" successfully******");    

            BasicDBObject query = new BasicDBObject();
            query.put("age", 5);
            DBCursor cursor = coll.find(query);
            while(cursor.hasNext()) {
            System.out.println(cursor.next());
            }

此代码不起作用。 Eclipse没有重新认识

coll.find(....)

如您所见：

Answer 1

您的collection变量是String。您应该将find(...)与coll变量一起使用。

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