MongoDB Java · W3School MongoDB 教程

# MongoDB Java 環境配置在Java程序中如果要使用MongoDB，你需要確保已經安裝了Java環境及MongoDB JDBC 驅動。你可以參考本站的[Java教程](/java/java-tutorial.html)來安裝Java程序。現在讓我們來檢測你是否安裝了 MongoDB JDBC 驅動。 * 首先你必須下載mongo jar包，下載地址：[https://github.com/mongodb/mongo-java-driver/downloads](https://github.com/mongodb/mongo-java-driver/downloads), 請確保下載最新版本。 * 你需要將mongo.jar包含在你的 classpath 中。。 ## 連接數據庫連接數據庫，你需要指定數據庫名稱，如果指定的數據庫不存在，mongo會自動創建數據庫。連接數據庫的Java代碼如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到 mongodb 服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 現在，讓我們來編譯運行程序并創建數據庫test。你可以更加你的實際環境改變MongoDB JDBC驅動的路徑。本實例將MongoDB JDBC啟動包 mongo-2.10.1.jar 放在本地目錄下: ``` $javac MongoDBJDBC.java $java -classpath ".:mongo-2.10.1.jar" MongoDBJDBC Connect to database successfully Authentication: true ``` 如果你使用的是Window系統，你可以按以下命令來編譯執行程序： ``` $javac MongoDBJDBC.java $java -classpath ".;mongo-2.10.1.jar" MongoDBJDBC Connect to database successfully Authentication: true ``` 如果用戶名及密碼正確，則Authentication 的值為true。 ## 創建集合我們可以使用com.mongodb.DB類中的createCollection()來創建集合代碼片段如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到 mongodb 服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); DBCollection coll = db.createCollection("mycol"); System.out.println("Collection created successfully"); }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 編譯運行以上程序，輸出結果如下: ``` Connect to database successfully Authentication: true Collection created successfully ``` ## 獲取集合我們可以使用com.mongodb.DBCollection類的 getCollection() 方法來獲取一個集合代碼片段如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到 mongodb 服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); DBCollection coll = db.createCollection("mycol"); System.out.println("Collection created successfully"); DBCollection coll = db.getCollection("mycol"); System.out.println("Collection mycol selected successfully"); }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 編譯運行以上程序，輸出結果如下: ``` Connect to database successfully Authentication: true Collection created successfully Collection mycol selected successfully ``` ## 插入文檔我們可以使用com.mongodb.DBCollection類的 insert() 方法來插入一個文檔代碼片段如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到 mongodb 服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); DBCollection coll = db.getCollection("mycol"); System.out.println("Collection mycol selected successfully"); BasicDBObject doc = new BasicDBObject("title", "MongoDB"). append("description", "database"). append("likes", 100). append("url", "http://www.w3cschool.cc/mongodb/"). append("by", "w3cschool.cc"); coll.insert(doc); System.out.println("Document inserted successfully"); }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 編譯運行以上程序，輸出結果如下: ``` Connect to database successfully Authentication: true Collection mycol selected successfully Document inserted successfully ``` ## 檢索所有文檔我們可以使用com.mongodb.DBCollection類中的 find() 方法來獲取集合中的所有文檔。此方法返回一個游標，所以你需要遍歷這個游標。代碼片段如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到 mongodb 服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); DBCollection coll = db.getCollection("mycol"); System.out.println("Collection mycol selected successfully"); DBCursor cursor = coll.find(); int i=1; while (cursor.hasNext()) { System.out.println("Inserted Document: "+i); System.out.println(cursor.next()); i++; } }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 編譯運行以上程序，輸出結果如下: ``` Connect to database successfully Authentication: true Collection mycol selected successfully Inserted Document: 1 { "_id" : ObjectId(7df78ad8902c), "title": "MongoDB", "description": "database", "likes": 100, "url": "http://www.w3cschool.cc/mongodb/", "by": "w3cschool.cc" } ``` ## 更新文檔你可以使用 com.mongodb.DBCollection 類中的 update() 方法來更新集合中的文檔。代碼片段如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到Mongodb服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到你的數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); DBCollection coll = db.getCollection("mycol"); System.out.println("Collection mycol selected successfully"); DBCursor cursor = coll.find(); while (cursor.hasNext()) { DBObject updateDocument = cursor.next(); updateDocument.put("likes","200") col1.update(updateDocument); } System.out.println("Document updated successfully"); cursor = coll.find(); int i=1; while (cursor.hasNext()) { System.out.println("Updated Document: "+i); System.out.println(cursor.next()); i++; } }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 編譯運行以上程序，輸出結果如下: ``` Connect to database successfully Authentication: true Collection mycol selected successfully Document updated successfully Updated Document: 1 { "_id" : ObjectId(7df78ad8902c), "title": "MongoDB", "description": "database", "likes": 100, "url": "http://www.w3cschool.cc/mongodb/", "by": "w3cschool.cc" } ``` ## 刪除第一個文檔要刪除集合中的第一個文檔，首先你需要使用com.mongodb.DBCollection類中的 findOne()方法來獲取第一個文檔，然后使用remove 方法刪除。代碼片段如下： ``` import com.mongodb.MongoClient; import com.mongodb.MongoException; import com.mongodb.WriteConcern; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.BasicDBObject; import com.mongodb.DBObject; import com.mongodb.DBCursor; import com.mongodb.ServerAddress; import java.util.Arrays; public class MongoDBJDBC{ public static void main( String args[] ){ try{ // 連接到Mongodb服務 MongoClient mongoClient = new MongoClient( "localhost" , 27017 ); // 連接到你的數據庫 DB db = mongoClient.getDB( "test" ); System.out.println("Connect to database successfully"); boolean auth = db.authenticate(myUserName, myPassword); System.out.println("Authentication: "+auth); DBCollection coll = db.getCollection("mycol"); System.out.println("Collection mycol selected successfully"); DBObject myDoc = coll.findOne(); col1.remove(myDoc); DBCursor cursor = coll.find(); int i=1; while (cursor.hasNext()) { System.out.println("Inserted Document: "+i); System.out.println(cursor.next()); i++; } System.out.println("Document deleted successfully"); }catch(Exception e){ System.err.println( e.getClass().getName() + ": " + e.getMessage() ); } } } ``` 編譯運行以上程序，輸出結果如下: ``` Connect to database successfully Authentication: true Collection mycol selected successfully Document deleted successfully ``` 你還可以使用 save(), limit(), skip(), sort() 等方法來操作MongoDB數據庫。