【转】Java操作Mongo实例(4)

6、 查询数据

@Test

public void query() {

    //查询所有

    //queryAll();

    //查询id = 4de73f7acd812d61b4626a77

    print("find id = 4de73f7acd812d61b4626a77: " + users.find(new BasicDBObject("_id", new ObjectId("4de73f7acd812d61b4626a77"))).toArray());

    //查询age = 24

    print("find age = 24: " + users.find(new BasicDBObject("age", 24)).toArray());

    //查询age >= 24

    print("find age >= 24: " + users.find(new BasicDBObject("age", new BasicDBObject("$gte", 24))).toArray());

    print("find age <= 24: " + users.find(new BasicDBObject("age", new BasicDBObject("$lte", 24))).toArray());

    print("查询age!=25：" + users.find(new BasicDBObject("age", new BasicDBObject("$ne", 25))).toArray());

    print("查询age in 25/26/27：" + users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.IN, new int[] { 25, 26, 27 }))).toArray());

    print("查询age not in 25/26/27：" + users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.NIN, new int[] { 25, 26, 27 }))).toArray());

    print("查询age exists 排序：" + users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.EXISTS, true))).toArray());

    print("只查询age属性：" + users.find(null, new BasicDBObject("age", true)).toArray());

    print("只查属性：" + users.find(null, new BasicDBObject("age", true), 0, 2).toArray());

    print("只查属性：" + users.find(null, new BasicDBObject("age", true), 0, 2, Bytes.QUERYOPTION_NOTIMEOUT).toArray());

    //只查询一条数据，多条去第一条

    print("findOne: " + users.findOne());

    print("findOne: " + users.findOne(new BasicDBObject("age", 26)));

    print("findOne: " + users.findOne(new BasicDBObject("age", 26), new BasicDBObject("name", true)));

    //查询修改、删除

    print("findAndRemove 查询age=25的数据，并且删除: " + users.findAndRemove(new BasicDBObject("age", 25)));

    //查询age=26的数据，并且修改name的值为Abc

    print("findAndModify: " + users.findAndModify(new BasicDBObject("age", 26), new BasicDBObject("name", "Abc")));

    print("findAndModify: " + users.findAndModify(

        new BasicDBObject("age", 28), //查询age=28的数据

        new BasicDBObject("name", true), //查询name属性

        new BasicDBObject("age", true), //按照age排序

        false, //是否删除，true表示删除

        new BasicDBObject("name", "Abc"), //修改的值，将name修改成Abc

        true, 

        true));

    queryAll();

}

mongoDB不支持联合查询、子查询，这需要我们自己在程序中完成。将查询的结果集在Java查询中进行需要的过滤即可。