Java与MongoDB数据库的CRUD（增删改查）

一、准备工作

1、建立maven项目，添加所需依赖

junit
junit
4.10
test


org.mongodb
mongo-java-driver
2.11.3

当然也可以建立java
project，下载mongoDB对Java支持的驱动包，然后拷贝jar文件到lib下

2、开启mongo服务，建立测试类进行测试

二、完整源码如下：

package com.shxt.mongo;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import org.bson.types.ObjectId;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
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.MongoClient;
import com.mongodb.util.JSON;
 /**
  * MongDB之CRUD
  * @author 范晓东
  * @ClassName: TestMongo
  * @Version 1.0
  * @ModifiedBy
  * @Copyright shxt
  * @date 2013-9-27 下午08:21:49
  * @description
  */
public class TestMongo {
        private Mongo mg = null;
        private DB db;
        private DBCollection users;
        @Before
        public void setUp() throws UnknownHostException {
                // 创建一个MongoDB的数据库连接对象
                mg=new MongoClient("localhost", 27017);
                //验证模式登录(如果不设置验证模块，可直接登录)
                //想要登录验证模块生效,需在命令行下输入1->mongo 2->use admin 3->db.addUser("root","root123"); 4->db.auth("root","root123");
                DB admin=mg.getDB("admin");
                boolean bool =admin.authenticate("root", "root123".toCharArray());
                if (bool){
                        //login success
                        //获得一个test的数据库，如果该数据库不存在，会自动创建
                        db=mg.getDB("test");
                }
                // 获取一个聚集集合DBCollection,相当于我们的数据库表
                users = db.getCollection("users");
        }
        @Test
        public void testQuery() {
                //查询所有的数据库
                for (String name : mg.getDatabaseNames()) {
                        System.out.println("dbName: " + name);
                }
                //查询所有的聚集集合
                for (String name : db.getCollectionNames()) {
                        System.out.println("collectionName: " + name);
                }
                //查询所有的数据
                DBCursor cur = users.find();
                while (cur.hasNext()) {
                        System.out.println(cur.next());
                }
                //其它
                System.out.println(cur.count());
                System.out.println(users.count());
                System.out.println(cur.getCursorId());
                System.out.println(JSON.serialize(cur));//JSON对象转换
        }
        @Test
        public void testQuery2(){
            //根据id查询
                List list=users.find(new BasicDBObject("_id", new ObjectId("5243871a0609f38c8a7a5ccd"))).toArray();
                System.out.println(list.get(0).get("name"));
                //根据age查询，从第一条开始取，取3条数据
                BasicDBObject user = new BasicDBObject();
                user.put("age", new BasicDBObject("$gte", 20));
                DBCursor cur=users.find(user).skip(0).limit(3);
                System.out.println(cur.count());
                while (cur.hasNext()) {
                        System.out.println(cur.next());
                }
            //查询age!=25
            //users.find(new BasicDBObject("age", new BasicDBObject("$ne", 25))).toArray();
            //查询age in 25/26/27
            //users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.IN, new int[] { 25, 26, 27 }))).toArray();
            //查询age not in 25/26/27
            //users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.NIN, new int[] { 25, 26, 27 }))).toArray();
                //查询存在age的数据
            //users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.EXISTS, true))).toArray();
            //只查询age属性
            //users.find(null, new BasicDBObject("age", true)).toArray();
            //只查询一条数据，多条取第一条
            //users.findOne();
            //users.findOne(new BasicDBObject("age", 26));
            //users.findOne(new BasicDBObject("age", 26), new BasicDBObject("name", true));
            //查询age=25的数据并删除
            //users.findAndRemove(new BasicDBObject("age", 25));
            //查询age=26的数据，并且修改name的值为abc
            //users.findAndModify(new BasicDBObject("age", 26), new BasicDBObject("name", "abc"));
        }
        @Test
        public void testAdd() {
                DBObject user = new BasicDBObject();
                user.put("name", "fxd");
                user.put("age", 21);
                user.put("sex", "男");
                users.save(user);
                //查看是否添加成功
                DBCursor cur = users.find();
                while (cur.hasNext()) {
                        System.out.println(cur.next());
                }
        }
        @Test
        public void testAdd2() {
                DBObject user1 = new BasicDBObject("name","张三");
                DBObject user2 = new BasicDBObject("age",20);
                users.insert(user1,user2);
                //查看是否添加成功
                DBCursor cur = users.find();
                while (cur.hasNext()) {
                        System.out.println(cur.next());
                }
        }
        @Test
        public void testAdd3() {
                DBObject user1 = new BasicDBObject("name","张三");
                DBObject user2 = new BasicDBObject("age",20);
                List list = new ArrayList();
                list.add(user1);
                list.add(user2);
                users.insert(list);
                //查看是否添加成功
                DBCursor cur = users.find();
                while (cur.hasNext()) {
                        System.out.println(cur.next());
                }
        }
        @Test
        public void testRemove(){
            users.remove(new BasicDBObject("_id", new ObjectId("524378680609ad5717421c6a")));
            //users.remove(new BasicDBObject("age", new BasicDBObject("$gte", 24)));
        }
        @Test
        public void update(){
                 //=update users set age=17 where name='fxd';
                 users.update(
                          new BasicDBObject("name","fxd"),//new BasicDBObject().append("name","fxd"),
                          new BasicDBObject("$set" ,new BasicDBObject("age",17)),
                  false,//如果users中不存在age字段，是否更新，false表示不更新
                  false//只修改第一条，true表示修改多条
                 );
        }
        @Test
        public void update2(){
                 //批量修改，也可以用users.update(),把第四个参数改为true即可
                 //=update users set age=age+10 where name='fxd';
                 users.updateMulti(
                          new BasicDBObject().append("name","fxd"),
                          new BasicDBObject("$inc",new BasicDBObject("age", 10))
                );
        }
        @After
        public void tearDown() {
                if (mg != null) {
                        if (db != null) {
                                // 结束Mongo数据库的事务请求
                                try {
                                        db.requestDone();
                                } catch (Exception e) {
                                        e.printStackTrace();
                                }
                        }
                        try {
                                mg.close();
                        } catch (Exception e) {
                                e.printStackTrace();
                        }
                        mg = null;
                        db = null;
                }
        }
}