MongoDB Driver相关

基本使用

//连接mongdb
MongoClient mongoClient = new MongoClient("localhost", 27017);
//指定数据库
DB db = mongoClient.getDB("mydb");
//指定集合
DBCollection coll = db.getCollection("mycol");
//插入文档{“name”: “mongo”, “info”: { “ver”: “3.0” } }
BasicDBObject doc = new BasicDBObject("name", "mongo").append("info", new BasicDBObject("ver", "3.0"));
coll.insert(doc);

//查找
// find all where i >= 50
BasicDBObject query = new BasicDBObject.append("i",
    new BasicDBObject.append(QueryOperators.GTE, 50));
DBCursor cursor = coll.find(query);
try {
    while (cursor.hasNext()) {
        System.out.println(cursor.next());
    }
} finally {
    cursor.close();
}

注意：
The MongoClient instance actually represents a pool of connections to the database; you will only need one instance of class MongoClient even with multiple threads.
Typically you only create one MongoClient instance for a given database cluster and use it across your application.
When creating multiple instances:
- All resource usage limits (max connections, etc) apply per MongoClient instance
- To dispose of an instance, make sure you call MongoClient.close() to clean up resources.

简单查询举例：

// 或 $or
BasicDBObject queryObject = new BasicDBObject().append(  
    QueryOperators.OR,  
    new BasicDBObject[] { 
        new BasicDBObject("id", 1),  
        new BasicDBObject("id", 2) 
    });
cursor = coll.find(queryObject ); 

// 且$and
queryObject = new BasicDBObject().append(
    QueryOperators.AND,  
    new BasicDBObject[] { 
        new BasicDBObject("id", 10),  
        new BasicDBObject("name", "10")
    });  
cursor = coll.find(queryObject );  

// 大于 $gt
queryObject = new BasicDBObject().append("id",
    new BasicDBObject().append(QueryOperators.GT, 10));  
cursor = coll.find(queryObject );  

// 大于等于 $gte  
queryObject = new BasicDBObject().append("id",
    new BasicDBObject().append(QueryOperators.GTE, 11));  
cursor = coll.find(queryObject );   

//小于 $lt  
queryObject = new BasicDBObject().append("id"
    new BasicDBObject().append(QueryOperators.LT, 2));  
cursor = coll.find(queryObject );   

//小于等于 $lte  
queryObject = new BasicDBObject().append("id",
    new BasicDBObject().append(QueryOperators.LTE, 2));  
cursor = coll.find(queryObject );