java mongodb 基础系列---查询，排序，limit，$in,$or,输出为list,创建索引,$ne 非操作

package com.infomorrow.webroot;

import java.util.List;

import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;

public class test_mongodb {
public static void  main(String args[]) throws Exception {
MongoClient        mongoClient = new MongoClient( "127.0.0.1" , 27017 );//建立连接
DB get_db_credit = mongoClient.getDB("credit_2");//数据库名
DBCollection collection = get_db_credit.getCollection("report");//集合名，对应mysql中的表名
BasicDBObject filter_dbobject = new BasicDBObject();

//建立查询条件,如果还有其他条件，类似的写即可
// 如:version=3,filter_dbobject.put("version", 3),mongod区分String 和 Integer类型，所以要小心"3"!=3
filter_dbobject.put("user_id", "10065716153075");

//下面执行查询，设置limit,只要10条数据,排序(类mysql orderby) 再建一个BasicDBObject即可，－1表示倒序
DBCursor cursor = collection.find(filter_dbobject).limit(10).sort(new BasicDBObject("create_time",-1));

//把结果集输出成list类型
 List<DBObject> list = cursor.toArray();
System.out.println(list.size());//list的长度
System.err.println(cursor.count());//计算结果的数量，类似于(mysql count()函数),不受limit的影响

//遍历结果集
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
}
}

@Test
public void testIn(){
//a=30或者a=50
DBObject queryCondition = new BasicDBObject();

  BasicDBList values = new BasicDBList();
values.add(30);
values.add(50);
queryCondition.put("a", new BasicDBObject("$in", values));

DBCursor dbCursor = coll.find(queryCondition);

}

@Test
public void testOrSingleField(){
DBObject queryCondition = new BasicDBObject();
//查询a<10 OR a>30
            BasicDBList values = new BasicDBList();
values.add(new BasicDBObject("a", new BasicDBObject("$gt", 30)));
values.add(new BasicDBObject("a", new BasicDBObject("$lt", 10)));
queryCondition.put("$or", values);

DBCursor dbCursor = coll.find(queryCondition);

}

values.add(new BasicDBObject("b", new BasicDBObject("$lt", 10)));

BasicDBObject basic=new BasicDBObject();
basic.put("name","amosli");
basic.put("hobby","code");
....
collection.find(basic).toArray();//将值转为list

// 创建索引
BasicDBObject obj = new BasicDBObject();
obj.put("create_time", -1);
collection.ensureIndex(obj);
// 查询索引,遍历索引
List<DBObject> list = collection.getIndexInfo();
for (DBObject o : list) {
System.out.println("\t" + o);
}

//not equal 非操作
BasicDBObject basicDBObject = new BasicDBObject("level","INFO");
System.out.println(collection.count(basicDBObject.append("status", new BasicDBObject("$ne",  "已完成"))));