Java操作MongoDB之CRUD（增删改查）

上一篇文章：MongoDB入门学习
http://blog.csdn.net/rjfxd/article/details/12108909
一、准备工作

1、建立maven项目，添加所需依赖

<dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

<version>4.10</version>

<scope>test</scope>

</dependency>

<dependency>

<groupId>org.mongodb</groupId>

<artifactId>mongo-java-driver</artifactId>

<version>2.11.3</version>

</dependency>

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<DBObject> 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<DBObject> list = new ArrayList<DBObject>();
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;
}
}
}

参考：
http://www.cnblogs.com/hoojo/archive/2011/06/02/2068665.html