一、准备工作

1、 首先,下载mongoDB对Java支持的驱动包 

驱动包下载地址:https://github.com/mongodb/mongo-java-driver/downloadsoDB

或者

在线查看源码:https://github.com/mongodb/mongo-java-driver

或者下载源码:

mongodb的eclipse可视化插件:

2、 下面建立一个JavaProject工程,导入下载下来的驱动包。即可在Java中使用mongoDB,

目录如下:

java 处理bit java 处理gdb数据_数据库


二、Java操作MongoDB示例

在本示例之前你需要启动mongod.exe的服务,启动后,下面的程序才能顺利执行;

 

1、 建立SimpleTest.java,完成简单的mongoDB数据库操作
Mongo mongo = new Mongo();// 连接本地的27017端口
// or
Mongo mongo = new Mongo( "localhost" ); // 默认端口27017
// or
Mongo mongo = new Mongo( "localhost" , 27017 ); // 指定主机与端口
连双台mongodb
//ip为主机ip地址,port为端口号,dataBaseName相当于数据库名
DBAddress left = new DBAddress("ip:port/dataBaseName");
 DBAddress right = new DBAddress("ip:port/dataBaseName ");
//若一个mongodb出现问题,会自动连另外一台
Mongo mongo = new Mongo(left, right);
连多台mongodb
List<ServerAddress> mongoHostList = new ArrayList<ServerAddress>();
mongoHostList.add(new ServerAddress("ip",port));
mongoHostList.add(new ServerAddress("ip",port));
mongoHostList.add(new ServerAddress("ip",port));
Mongo mg = new Mongo(mongoHostList);

这样就创建了一个MongoDB的数据库连接对象,它默认连接到当前机器的localhost地址,端口是27017。

用户认证(可选)

在登录数据库时,在数据库启动时可以指定是否需要认证(

mongod --auth --dbpath e:\data   
//前提是要把E:\mongodb\bin加到环境变量
),
此时连接时就需要用户名和密码(--serviceUser xx --servicePassword xx),如下:
boolean auth = db.authenticate(myUserName, myPassword);
DB db = mongo.getDB(“test”);

这样就获得了一个test的数据库,如果mongoDB中没有创建这个数据库也是可以正常运行的。因为mongoDB可以在没有创建这个数据库的情况下,完成数据的添加操作。当添加的时候,没有这个库,mongoDB会自动创建当前数据库。

注意:mongodb区分大小写,程序中一定要注意

得到了db,下一步我们要获取一个“聚集集合DBCollection”,通过db对象的getCollection方法来完成。

DBCollection users = db.getCollection("users");
这样就获得了一个DBCollection,它相当于我们数据库的“表”。
查询所有数据
DBCursor cur = users.find();
while (cur.hasNext()) {
System.out.println(cur.next());
}

完整代码:

package com.syz;
import java.net.UnknownHostException;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
public class SimpleTest {
/**
 * @param args
 * @throws MongoException 
 * @throws UnknownHostException 
 */
public static void main(String[] args) throws UnknownHostException, MongoException {
Mongo mongo = new Mongo();
DB db = mongo.getDB("test");
DBCollection users = db.getCollection("sss");
是指test数据库里面的一个集合
DBCursor cur = users.find();
while(cur.hasNext()){
   System.out.println(cur.next());
}
}
}

简单例子:

public class SimpleTest {
    public static void main(String[] args) throws UnknownHostException, MongoException {
        Mongo mg = new Mongo();
        //查询所有的Database
        for (String name : mg.getDatabaseNames()) {
            System.out.println("dbName: " + name);
        }
       
        DB db = mg.getDB("test");
        //查询所有的聚集集合
        for (String name : db.getCollectionNames()) {
            System.out.println("collectionName: " + name);
        }
        DBCollection users = db.getCollection("sss");
       
        //查询所有的数据
        DBCursor cur = users.find();
        while (cur.hasNext()) {
            System.out.println(cur.next());
        }
      
         System.out.println("记录数:"+cur.count());
         System.out.println("游标ID:"+cur.getCursorId());
         System.out.println("JSON格式:"+JSON.serialize(cur));    }
}
2、 完成CRUD操作,首先建立一个MongoDBCRUDTest.java,基本测试代码如下:
package com.hoo.test;
 
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.Bytes;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
import com.mongodb.QueryOperators;
import com.mongodb.util.JSON;
 
public class MongoDBCRUDTest {
   
    private Mongo mg = null;
    private DB db;
    private DBCollection users;
   
    @Before
    public void init() {
        try {
            mg = new Mongo();
            //mg = new Mongo("localhost", 27017);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (MongoException e) {
            e.printStackTrace();
        }
        //获取temp DB;如果默认没有创建,mongodb会自动创建
        db = mg.getDB("temp");
   //db.addUser("xiaoshi", "bar");  在mongodb.exe窗口中新增的一个用户
  if(db.authenticate("xiaoshi", "bar".toCharArray())){//如果用户名密码对的话
        //获取users DBCollection;如果默认没有创建,mongodb会自动创建
        users = db.getCollection("users");
        //获取users DBCollection;如果默认没有创建,mongodb会自动创建
        users = db.getCollection("users");
      }
    }
 
    @After
    public void destory() {
        if (mg != null)
            mg.close();
        mg = null;
        db = null;
        users = null;
        System.gc();
    }
   
    public void print(Object o) {
        System.out.println(o);
    }
}
3、 添加操作
在添加操作之前,我们需要写个查询方法,来查询所有的数据。代码如下:
        private void queryAll() {
         print("查询users的所有数据:");
         //db游标
         DBCursor cur = users.find();
          while (cur.hasNext()) {
              print(cur.next());
        }
      }
     
    @Test
    public void add() {
        //先查询所有数据
        queryAll();
        print("count: " + users.count());
       
        DBObject user = new BasicDBObject();
        user.put("name", "shiyz");
        user.put("age", 24);
        //users.save(user)保存,getN()获取影响行数
        //print(users.save(user).getN());
       
        //扩展字段,随意添加字段,不影响现有数据
        user.put("sex", "男");
        print(users.save(user).getN());
       
        //添加多条数据,传递Array对象
        DBObject user1 = new BasicDBObject("name", "holy");
        user1.put("name", "dddd");
        user1.put("age", 24);
  print(users.insert(user1, new BasicDBObject("name", "lijn")).getN());
        //把user1换成user则会插入失败
        // print(users.insert(user, new BasicDBObject("name", "lijn")).getN());
        
        //添加List集合
        List<DBObject> list = new ArrayList<DBObject>();
        DBObject user2 = new BasicDBObject("name", "holy");
        user2.put("age", 27);
        list.add(user2);
        DBObject user3 = new BasicDBObject("name", "jeloo");
        user3.put("age", 28);
        list.add(user3);
        user3.put("sex", true);
        list.add(user3);//user3只会插入一次
        //添加List集合
        print(users.insert(list).getN());
        
        ArrayList al = new ArrayList();  
        DBObject tt = new BasicDBObject();  
        tt.put("companyID", "BJ_002");  
        tt.put("companyTel", "0571-88888888");  
        al.add(tt);  
        DBObject tt1 = new BasicDBObject("name", "huanglq");  
        tt1.put("companyID", "BJ_003");  
        tt1.put("companyTel", "0571-88889999");  
        al.add(tt1);  
        users.insert(al);  
        
        //查询下数据,看看是否添加成功
        print("count: " + users.count());
        queryAll();
    }
4、 删除数据
   @Test
   public void remove() {
        queryAll();
        //id不存在也不会报错
        print("删除id = 50149c799dbbbcd9be55652c:" + users.remove(new BasicDBObject("_id", new ObjectId("50149c799dbbbcd9be55652c"))).getN());
        //print("删除name = dddd:" + users.remove(new BasicDBObject("name","dddd")).getN());
        //print("remove age >= 24: " + users.remove(new BasicDBObject("age", new BasicDBObject("$gte", 24))).getN());
        queryAll();
    }
5、 修改数据
@Test
    public void update() {
       //print("修改:" + users.update(new BasicDBObject("_id", new ObjectId("50149eb79dbb04f61b17501d")), new BasicDBObject("age", 99)).getN());
      /*  print("修改:" + users.update(
                new BasicDBObject("_id", new ObjectId("5014a10a5630000000003e16")),
                new BasicDBObject("age", 66),
                true,//如果数据库不存在,是否添加
                false//false只修改第一条,true不修改
                ).getN()); */
      /*  print("修改:" + users.update(
                new BasicDBObject("name", "huanglq"),
                new BasicDBObject("name", "lllll"),
                true,//如果数据库不存在,是否添加
                false//false只修改第一条,true不修改
                ).getN());*/
    // print(users.update(new BasicDBObject("companyID","BJ_002"),new BasicDBObject("companyID","BJ_00ww")).getN()); //多条记录也只会修改第一条
    /*//整个对象重新全部修改
       BasicDBObject newDocument =new BasicDBObject();//多条也是只修改第一条
           newDocument.put("companyID", "BJ_00ww");
           newDocument.put("type", "shared host");
           newDocument.put("clients", 222);
       users.update(new BasicDBObject().append("companyID", "BJ_00ww"), newDocument);
     */  
    /*   //比如要把hosting中值为BJ_00ww的document中的type的值进行修改, //多条也是只修改第一条
           BasicDBObject newDocument3 =new BasicDBObject().append("$set",
       new BasicDBObject().append("name", "shiyz"));
           users.update(new BasicDBObject().append("name", "buding"), newDocument3);
              */
           
         /*  //如果要更新多个document中相同的值,可以使用$multi,比如,要把所有name为shiyz的document,将它们的name的值更新为buding,
            BasicDBObject updateQuery =new BasicDBObject().append("$set",
        new BasicDBObject().append("name", "buding"));
            users.update(new BasicDBObject().append("name", "shiyz"), updateQuery, false, true);
          */
            queryAll();
    }
6、 查询数据
  @Test
    public void query() {
        //查询所有
        //queryAll();
       
        //查询id = 50149c799dbbbcd9be556530
print("find id = 50149c799dbbbcd9be556530: " + users.find(new BasicDBObject("_id",new ObjectId("50149c799dbbbcd9be556530"))).toArray());
       
        //查询age = 24
        // print("find age = 24: " + users.find(new BasicDBObject("age", 24)).toArray());
       
        //查询age >= 24
        //print("find age >= 24: " + users.find(new BasicDBObject("age", new BasicDBObject("$gte", 24))).toArray());
        //查询age <= 24
        // print("find age <= 24: " + users.find(new BasicDBObject("age", new BasicDBObject("$lte", 24))).toArray());
        
        //print("查询age!=25:" + users.find(new BasicDBObject("age", new BasicDBObject("$ne", 25))).toArray());
       // print("查询age in 25/26/27:" + users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.IN, new int[] { 25, 26, 27 }))).toArray());
       // print("查询age not in 25/26/27:" + users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.NIN, new int[] { 25, 26, 27 }))).toArray());
       // print("查询age exists 排序:" + users.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.EXISTS, true))).toArray());
        /*
        print("只查询age属性:" + users.find(null, new BasicDBObject("age", true)).toArray());
        print("只查属性:" + users.find(null, new BasicDBObject("age", true), 0, 2).toArray());
        print("只查属性:" + users.find(null, new BasicDBObject("age", true), 0, 2, Bytes.QUERYOPTION_NOTIMEOUT).toArray());
       
        //只查询一条数据,多条取第一条
        print("findOne: " + users.findOne());
        print("findOne: " + users.findOne(new BasicDBObject("age", 26)));
        print("findOne: " + users.findOne(new BasicDBObject("age", 26), new BasicDBObject("name", true)));
       
        //查询修改、删除
        print("findAndRemove 查询age=25的数据,并且删除: " + users.findAndRemove(new BasicDBObject("age", 25)));
       
        //查询age=26的数据,并且修改name的值为Abc
        print("findAndModify: " + users.findAndModify(new BasicDBObject("age", 26), new BasicDBObject("name", "Abc")));
        print("findAndModify: " + users.findAndModify(
            new BasicDBObject("age", 28), //查询age=28的数据
            new BasicDBObject("name", true), //查询name属性
            new BasicDBObject("age", true), //按照age排序
            false, //是否删除,true表示删除
            new BasicDBObject("name", "Abc"), //修改的值,将name修改成Abc
            true,
            true));*/
//查询id大于等于1的记录,并且只取10条记录
DBCursor cur = users.find(new BasicDBObject("_id",new BasicDBObject("$gte",1))).limit(10);
while(cur.hasNext()){
System.out.println(cur.next());
}
//查询id大于等于1的记录,并按id进行降序 -1表示降序,1升序。
DBCursor cur = users.find(new BasicDBObject("_id",new BasicDBObject("$gte",1))).sort(new BasicDBObject("_id",-1));
while(cur.hasNext()){
System.out.println(cur.next());
}
//查询id大于等于1的记录,并跳过前10条记录显示 相当于id>10
DBCursor cur = users.find(new BasicDBObject("_id",new BasicDBObject("$gte",1))).skip(10);
while(cur.hasNext()){
System.out.println(cur.next());
}
//查询id大于等于1的记录,跳过前10条记录并且只显示10条记录。相当//于分页功能where id>10 and id<=20
DBCursor cur = users.find(new BasicDBObject("_id",new BasicDBObject("$gte",1))).skip(10).limit(10);
while(cur.hasNext()){
System.out.println(cur.next());
}
       
    }
mongoDB不支持联合查询、子查询,这需要我们自己在程序中完成。将查询的结果集在Java查询中进行需要的过滤即可。
7、 其他操作
public void testOthers() {
    DBObject user = new BasicDBObject();
    user.put("name", "hoojo");
    user.put("age", 24);
   
    //JSON 对象转换       
    print("serialize: " + JSON.serialize(user));
    //反序列化
    print("parse: " + JSON.parse("{ \"name\" : \"hoojo\" , \"age\" : 24}"));
   
    print("判断temp Collection是否存在: " + db.collectionExists("temp"));
   
    //如果不存在就创建
    if (!db.collectionExists("temp")) {
        DBObject options = new BasicDBObject();
        options.put("size", 20);
        options.put("capped", 20);
        options.put("max", 20);
        print(db.createCollection("account", options));
    }
    //设置db为只读
    db.setReadOnly(true);
    //只读不能写入数据
    db.getCollection("test").save(user);
}