MongoDB：如何使用Java驱动程序获取包含数组的所有元素？

Question

How would you write this MongoDB query using Java driver :

db.customers.find({'arrayName' : {$exists:true}, $where:'this.arrayName.length>0'})

Cheers, Yann

Answer 1

To build a query with the Java driver, you substitute any Javascript objects with DBObject 's.

DBObject condition = new BasicDBObject();
condition.put("arrayName", new BasicDBObject("$exists", true));
condition.put("$where",  "this.arrayName.length>0");

DBCursor result = yourDatabase.getCollection("customers").find(condition);