利用JAVA操作MongoDB

package com.hoo.test;
  
import java.net.UnknownHostException;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;

import com.mongodb.util.JSON;


/**
 

 * <b>function:</b>MongoDB 简单示例
 

 * @author flychao88
  

 * @file SimpleTest.java
 

 * @package com.hoo.test
 

 * @project MongoDB
  

 * @version 1.0
 

 */
 

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("users");
  

        //查询所有的数据
 

        DBCursor cur = users.find();
 

        while (cur.hasNext()) {
 

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

        }
 

        System.out.println(cur.count());
 

        System.out.println(cur.getCursorId());
 

        System.out.println(JSON.serialize(cur));
 

    }
 

}
 

  

2、 完成CRUD操作，首先建立一个MongoDB4CRUDTest.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;
 

/**
 
 * <b>function:</b>实现MongoDB的CRUD操作
  
 * @package com.hoo.test
 
 * @project MongoDB
  
 */
 
public class MongoDB4CRUDTest {
  
    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");
 
        //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： 

/**
 
 * <b>function:</b> 查询所有数据
  
 */
 
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", "hoojo");
 
    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
 
    print(users.insert(user, new BasicDBObject("name", "tom")).getN());
  
    //添加List集合
 
    List<DBObject> list = new ArrayList<DBObject>();
 
    list.add(user);
 
    DBObject user2 = new BasicDBObject("name", "lucy");
 
    user.put("age", 22);
 
    list.add(user2);
 
    //添加List集合
 
    print(users.insert(list).getN());
 
    //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();
 
    print("删除id = 4de73f7acd812d61b4626a77：" + users.remove(new BasicDBObject("_id", new ObjectId("4de73f7acd812d61b4626a77"))).getN());
 
    print("remove age >= 24: " + users.remove(new BasicDBObject("age", new BasicDBObject("$gte", 24))).getN());
 
}
  

5、 修改数据 

@Test
 
public void modify() {
 
    print("修改：" + users.update(new BasicDBObject("_id", new ObjectId("4dde25d06be7c53ffbd70906")), new BasicDBObject("age", 99)).getN());
 
    print("修改：" + users.update(
 
            new BasicDBObject("_id", new ObjectId("4dde2b06feb038463ff09042")), 
 
            new BasicDBObject("age", 121),
 
            true,//如果数据库不存在，是否添加
 
            false//多条修改
 
            ).getN());
 
    print("修改：" + users.update(
 
            new BasicDBObject("name", "haha"), 
 
            new BasicDBObject("name", "dingding"),
 
            true,//如果数据库不存在，是否添加
 
            true//false只修改第一天，true如果有多条就不修改
 
            ).getN());
  
    //当数据库不存在就不修改、不添加数据，当多条数据就不修改
 
    //print("修改多条：" + coll.updateMulti(new BasicDBObject("_id", new ObjectId("4dde23616be7c19df07db42c")), new BasicDBObject("name", "199")));
 
}
  

6、 查询数据 

@Test
 
public void query() {
 
    //查询所有
 
    //queryAll();
 

    //查询id = 4de73f7acd812d61b4626a77
 
    print("find id = 4de73f7acd812d61b4626a77: " + users.find(new BasicDBObject("_id", new ObjectId("4de73f7acd812d61b4626a77"))).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());
 
    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，多条去第一条
 
    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));
 
     
    queryAll();
 
}
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);
 
}