"最近用到了 MongDB，就把所学的记录下。首先上官网上下载最新的版本[链接] 解压后配置数据库路径，例如我的在 D:\MongoDB，数据库路径是 D:\MongoDB\data 在 bin 文件夹下输入命令 mongod --dbpath D:\MongoDB\data，接着再输入 mongo ...."

someone1
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AI开发者社区 • 0 回帖 • 6 浏览 • 6 个月前

MongoDB的基本使用

最近用到了 MongDB，就把所学的记录下。

首先上官网上下载最新的版本http://www.mongodb.org/downloads

解压后配置数据库路径，例如我的在 D:\MongoDB，数据库路径是 D:\MongoDB\data

在 bin 文件夹下输入命令 mongod --dbpath D:\MongoDB\data，接着再输入 mongo 看看连接情况，若出现

Mongo Shell version：x.x.x

connecting to： test

则说明配置成功了，接下来我们就可以使用自己的 mongdb 了。

对于数据库的基本使用也就是增删改查了

package edu.scut.italk.mongodb;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import org.bson.types.ObjectId;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import com.mongodb.MongoOptions;
import edu.scut.log4j.Logs;
/**

mongodb 操作的工具类


*/
public class DBUtil {
private static MongoClient mongoClient = null;
private static DB db = null;
private static DBCollection dbCollection = null;
</span><span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> {
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        mongoClient </span>= <span style="color: rgba(0, 0, 255, 1)">new</span> MongoClient("127.0.0.1", 27017<span style="color: rgba(0, 0, 0, 1)">);
        db </span>= mongoClient.getDB("test"<span style="color: rgba(0, 0, 0, 1)">);
        db.createCollection(</span>"chatlogs", <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">);
        dbCollection </span>= db.getCollection("chatlogs"<span style="color: rgba(0, 0, 0, 1)">);
    } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (UnknownHostException e) {</span>

            e.printStackTrace();
}
}
</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 设置唯一性
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> field 要设置的field
 </span><span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> setUnique(String field) {
    BasicDBObject basicDBObject </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> BasicDBObject();
    basicDBObject.put(field, </span>1<span style="color: rgba(0, 0, 0, 1)">);
    
    dbCollection.ensureIndex(basicDBObject, </span>"unique_key_name", <span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">);
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 插入数据库
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> doc
 </span><span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> insert(DBObject... doc) {
    dbCollection.insert(doc);
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 保存修改，如果数据库中不存在则插入，否则覆盖
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> dbCollection
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> dbObject 要保存的对象
 * </span><span style="color: rgba(128, 128, 128, 1)">@return</span>
 <span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> DBObject save(DBObject dbObject) {
    dbCollection.save(dbObject);
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> dbObject;
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 根据id查找并返回得到的BasicObject对象
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> dbCollection
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> id
 * </span><span style="color: rgba(128, 128, 128, 1)">@return</span>
 <span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject findById(String id) {
    BasicObject basicObject </span>= <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">;
    BasicObject query </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject();
    query.put(</span>"_id", <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> ObjectId(id));
    DBObject mOb </span>=<span style="color: rgba(0, 0, 0, 1)"> dbCollection.findOne(query);
    </span><span style="color: rgba(0, 0, 255, 1)">if</span>(<span style="color: rgba(0, 0, 255, 1)">null</span> !=<span style="color: rgba(0, 0, 0, 1)"> mOb)
        basicObject </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject(mOb.toMap());
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> basicObject;
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 查找children域为null的basicObject对象
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> dbCollection
 * </span><span style="color: rgba(128, 128, 128, 1)">@return</span><span style="color: rgba(0, 128, 0, 1)"> 返回一个包含多个basicobject对象的list
 </span><span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> List&lt;BasicObject&gt;<span style="color: rgba(0, 0, 0, 1)"> findNoChildren() {
    BasicObject basicObject </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject();
    basicObject.setChildren(</span><span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">);
    DBCursor dbCursor </span>=<span style="color: rgba(0, 0, 0, 1)"> dbCollection.find(basicObject);
    List</span>&lt;BasicObject&gt; list = <span style="color: rgba(0, 0, 255, 1)">new</span> ArrayList&lt;BasicObject&gt;<span style="color: rgba(0, 0, 0, 1)">();
    </span><span style="color: rgba(0, 0, 255, 1)">for</span><span style="color: rgba(0, 0, 0, 1)"> (DBObject dbObject : dbCursor) {
        list.add(</span><span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject(dbObject.toMap()));
    }
    dbCursor.close();
    
    </span><span style="color: rgba(0, 0, 255, 1)">return</span> list.size() &gt; 0 ? list : <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">;
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 根据content查找并返回得到的BasicObject对象
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> dbCollection
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> content
 * </span><span style="color: rgba(128, 128, 128, 1)">@return</span>
 <span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject findByContent(String content) {
    BasicObject basicObject </span>= <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">;
    DBObject mOb </span>= dbCollection.findOne(<span style="color: rgba(0, 0, 255, 1)">new</span> BasicObject("content"<span style="color: rgba(0, 0, 0, 1)">, content));
    </span><span style="color: rgba(0, 0, 255, 1)">if</span>(<span style="color: rgba(0, 0, 255, 1)">null</span> !=<span style="color: rgba(0, 0, 0, 1)"> mOb)
        basicObject </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> BasicObject(mOb.toMap());
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> basicObject;
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 遍历全部
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@return</span>
 <span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> DBCursor findAll() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> dbCollection.find();
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> remove(DBObject dbObject) {
    dbCollection.remove(dbObject);
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 关闭mongoclient
 </span><span style="color: rgba(0, 128, 0, 1)">*/</span>
<span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> closeClient() {
    </span><span style="color: rgba(0, 0, 255, 1)">if</span>(<span style="color: rgba(0, 0, 255, 1)">null</span> !=<span style="color: rgba(0, 0, 0, 1)"> mongoClient) {
        mongoClient.close();
    }
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> dropDB() {
    db.dropDatabase();
}

}

以上基本把我们需要的操作都加载该工具类中，

使用时像这样

        System.out.println("==================findAll============================");
        DBCursor dbCursor = DBUtil.findAll();
        for (DBObject dbObject : dbCursor) {System.out.println(dbObject);
        }
        dbCursor.close();
        System.out.println("=====================================================");

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