Java操作MongoDB

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<DBObject> 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); }}