mongodb 小操作

mongodb-driver.jar操作数据库

collection是DBCollection对象

添加数据

collection.save(new BasicDBObject("author", "yinjihuan").append("title", "mongodb"));

编辑数据

collection.update(new BasicDBObject("author", "yinjihuan"),

new BasicDBObject("$set", new BasicDBObject("title", "mongodb3.0")));

删除数据

collection.remove(new BasicDBObject("author", "yinjihuan"));

查询所有数量

long count = collection.count();

查询所有数据

DBCursor cursor = collection.find();

while (cursor.hasNext()) {

DBObject data = cursor.next();

System.out.println(data.toString());

}

查询第一条数据

DBObject data = collection.findOne();

带条件查询

DBObject query = new BasicDBObject("author", "yinjihuan");

cursor = collection.find(query);

大于(gt)查询

query = new BasicDBObject("visit_count", new BasicDBObject("$gt", 10));

cursor = collection.find(query);

小于(lt)查询

query = new BasicDBObject("visit_count", new BasicDBObject("$lt", 10));

cursor = collection.find(query);

查询固定的列

query = new BasicDBObject("author", "yinjihuan");

DBObject fields = new BasicDBObject("author", 1);

cursor = collection.find(query, fields);

分页查询,当数据量较大的时候不建议使用skip,会很慢的

建议按id排序,每查询一页记住最后一条id,然后大于id在limit

query = new BasicDBObject("author", "yinjihuan");

cursor = collection.find(query, fields).skip(0).limit(10);

创建索引

collection.createIndex(new BasicDBObject("author_idx", 1));