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Java操作MongoDB

首先需要添加进入Java-MongoDB驱动包

java操作Mongodb常用的几个类：

Mongo：连接服务器，执行一些数据库操作的选项，如新建立一个数据库等

DB：对应一个数据库，可以用来建立集合等操作

DBCollection：对应一个集合（类似表），可能是我们用得最多的，可以添加删除记录等

DBObject接口和BasicDBObject对象：表示一个具体的记录，BasicDBObject实现了DBObject，是key-value的数据结构，用起来和HashMap是基本一致的。

DBCursor：用来遍历取得的数据，实现了Iterable和Iterator

具体实现：

package m1;import java.util.Arrays;import java.util.LinkedList;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.Mongo;import com.mongodb.QueryOperators;/** * Java对MongoDB的操作 * @author linziyu * */public class TT {	Mongo mongo;	public TT(Mongo mongo) {		this.mongo = mongo;			}		/**	 * 插入一条文档	 */	public void insert() {		DB db = mongo.getDB("data1");		DBCollection collection = db.getCollection("user");		BasicDBObject basicDBObject = new BasicDBObject();		basicDBObject.put("name", "KKK");		basicDBObject.put("age",15);		basicDBObject.put("sex","man");		collection.insert(basicDBObject);	}		public void insert_Many() {		DB db = mongo.getDB("data1");		DBCollection collection = db.getCollection("u1");		List
   
     objects = new LinkedList<>();		objects.add(new BasicDBObject("name","a").append("age",77).append("sex","woman"));		objects.add(new BasicDBObject("name","b").append("age",99).append("sex","woman"));		objects.add(new BasicDBObject("name","c").append("age",99).append("sex","woman"));		objects.add(new BasicDBObject("name","d").append("age",99).append("sex","woman"));		objects.add(new BasicDBObject("name","e").append("age",99).append("sex","woman"));		collection.insert(objects);	}		/**	 * 读取所有记录	 */	public void read_ALL() {		DB db = mongo.getDB("data1");		DBCollection collection = db.getCollection("u1");		DBCursor cursor = collection.find();		while (cursor.hasNext()) {			DBObject object = cursor.next();			System.out.println(object);					}			}		/**	 * 读取数据	 * 	 */	public void read() {		DB db = mongo.getDB("data1");		DBCollection collection = db.getCollection("u1");		DBCursor cursor = collection.find();		while (cursor.hasNext()) {			BasicDBObject basicDBObject = (BasicDBObject) cursor.next();			if (basicDBObject!=null) {				System.out.println(basicDBObject.getString("name"));				System.out.println(basicDBObject.getInt("age"));				System.out.println(basicDBObject.getString("sex"));							}					}	}		/**	 * 条件查询(查找name值为ppp的对象)	 */	public void find() {		DB db = mongo.getDB("data1");		DBCollection collection = db.getCollection("user");		BasicDBObject queryObject = new BasicDBObject("name","ppp");		DBObject object = collection.findOne(queryObject);		System.out.println(object.get("age"));	}			/**	 * 条件查询(查找年龄大于23并且sex值为woman的对象)	 */	public void find_1() {		 DB db = mongo.getDB("data1");		 DBCollection collection = db.getCollection("user");		 BasicDBObject ageObj = new BasicDBObject("age",new BasicDBObject("$gt",23));	     BasicDBObject sexObj = new BasicDBObject("sex","woman");	     BasicDBObject andObj = new BasicDBObject("$and",Arrays.asList(ageObj,sexObj));	     DBCursor cursor = collection.find(andObj);	     while(cursor.hasNext()){	                DBObject obj = cursor.next();	                System.out.println(obj.toString());	        }			}		/**	 * 更新数据(把表中字段age都改成55)	 */	public void update() {		 DB db = mongo.getDB("data1");		 DBCollection collection = db.getCollection("u1");		 DBCursor cursor = collection.find();		 BasicDBObject doc = new BasicDBObject();		 BasicDBObject res = new BasicDBObject();		 res.put("age",55);		 doc.put("$set",res);		 collection.update(new BasicDBObject(),doc,false,true);		 		 	}		/**	 * 删除(删除name为a的记录)	 */	public void delete() {		 DB db = mongo.getDB("data1");		 DBCollection collection = db.getCollection("u1");		 BasicDBObject object = new BasicDBObject();		 object.put("name","a");		 collection.remove(object);		 			}		}
   

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