MongoDB——Java操作（增删改查）

Java操作MongoDB，下面是一个完整的例子。本实例需导入mongo-2.5.3.jar

Java代码




import java.net.UnknownHostException;

import java.util.Iterator;

import java.util.Set;

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.MongoException;

public class MongoMain {

static DB db = null;

static DBCollection coll = null;

static {

Mongo m = null;

try {

//m = new Mongo();//默认本地

//m = new Mongo("127.0.0.1");//默认端口

m = new Mongo("127.0.0.1",27017);

} catch (UnknownHostException e) {

e.printStackTrace();

} catch (MongoException e) {

e.printStackTrace();

}

//获取名为 test 的数据库，不存在的情况下创建

db = m.getDB("test");

//登录数据库（用户名:test，密码:test）

boolean auth = db.authenticate("test", "test".toCharArray());

if(auth){

//只有admin中的用户才有此权限(show dbs)

//获取所有数据库，不显示无collection的db

//System.out.println("所有数据库名："+m.getDatabaseNames());

//获取名为 user 的collection(相当于表)，不存在的情况下创建

coll = db.getCollection("user");

}else{

System.out.println("登录失败!");

}

}

public static void main(String[] args) {

MongoMain test = new MongoMain();

if(coll!=null){

test.saveData();

test.searchData();

test.updateData();

test.deleteData();

}

}

/**

* 保存数据

*/

public void saveData(){

//录入学生1的信息

BasicDBObject stu1 = new BasicDBObject();

stu1.put("name", "jack");

stu1.put("age", "25");

BasicDBObject sight1 = new BasicDBObject();

sight1.put("left", 1.5);

sight1.put("right", 1.2);

stu1.put("sight", sight1);

//录入学生2的信息

BasicDBObject stu2 = new BasicDBObject();

stu2.put("name", "lucy");

stu2.put("age", "22");

BasicDBObject sight2 = new BasicDBObject();

sight2.put("left", 1.0);

sight2.put("right", 1.3);

stu2.put("sight", sight2);

//注意：不能直接对sight赋值{left:1.0,right:1.3}

coll.insert(stu1);

coll.insert(stu2);

}

/**

* 查询数据

*/

public void searchData(){

System.out.println("=======================");

//show collections

//获取数据库下所有的collection，不显示无数据的collection

Set<String> colls = db.getCollectionNames();

showData(colls);

System.out.println("=======================");

//查询coll中全部记录

DBCursor ite = coll.find();

showData(ite);

System.out.println("=======================");

//获取第一条记录

DBObject o = coll.findOne();

System.out.println(o);

System.out.println("=======================");

//统计colletion的数据条数

System.out.println(coll.getCount());

System.out.println("=======================");

//查询 name为jack的对象

BasicDBObject query = new BasicDBObject();

query.put("name", "jack");

DBCursor it = coll.find(query);

showData(it);

System.out.println("=======================");

//查询age小于30，age不等于20的对象

BasicDBObject query2 = new BasicDBObject();

query2.put("age", new BasicDBObject("$lt", 30));

query2.put("age", new BasicDBObject("$ne", 20));

DBCursor it2 = coll.find(query2);

showData(it2);

}

/**

* 修改数据

*/

public void updateData(){

BasicDBObject query = new BasicDBObject();

query.put("name", "lucy");

//这里的new_info对象一定要是find出的而不是new的，否则多字段的情况下就会丢失其它字段信息

DBObject new_info = coll.findOne(query);

//方法一（缺点，必须把2个值都put进去）

BasicDBObject sight = new BasicDBObject();

sight.put("left", 1.3);

sight.put("right", 1.3);

new_info.put("sight", sight);

//方法二（优点，只需设置要修改的字段的值）

DBObject obj = (DBObject)new_info.get("sight");

obj.put("right", 1.5);

coll.update(query, new_info);

}

/**

* 删除数据

*/

public void deleteData(){

BasicDBObject data = new BasicDBObject();

//删除名称为lucy的记录

data.put("name", "lucy");

//传入[空实例]删除所有

coll.remove(data);

}

/**

* 遍历显示结果

* @param result

*/

@SuppressWarnings("rawtypes")

public void showData(Iterable result){

Iterator it = result.iterator();

while(it.hasNext())

{

System.out.println(it.next());

}

}

}

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原文链接：
http://blog.csdn.net/wangkuifeng0118/article/details/6958922