java操作mysql數據庫的代碼我們已經了如指掌了，增刪改查，java對mongodb數據庫也是類似的操作，先是數據庫連接，再是進行操作。
首先我們進入進入admin數據庫，然后建立自己的數據庫testMongoDb，進入admin數據庫后，就可以直接進入testMongoDb，因為用戶可以進入系統的數據庫，就是超級管理員，use testMongoDb后，為該數據庫設置用戶名和密碼，db.addUser('root','root')，這樣我們在程序中連該數據庫，并實現增刪改查，代碼如下所示。
代碼如下所示：
復制代碼 代碼如下:
package com.mkyong.core;
import java.net.UnknownHostException;
import java.util.Date;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.Mongo;
import com.mongodb.MongoException;
/**
* Java + MongoDB Hello world Example
*
*/
public class App {
public static void main(String[] args) {
try {
/**** Connect to MongoDB ****/
// Since 2.10.0, uses MongoClient
//MongoClient mongo = new MongoClient("localhost", 27017);
Mongo mongo = new Mongo("127.0.0.1",27017);
/**** Get database ****/
// if database doesn't exists, MongoDB will create it for you
DB db = mongo.getDB("testMongoDb");
//database username root and password root
boolean ok = db.authenticate("root","root".toCharArray());
if(ok){
System.out.println("db connection success！");
}{
System.out.println("db connection fail ！");
}
/**** Get collection / table from 'testMongoDb' ****/
// if collection doesn't exists, MongoDB will create it for you
DBCollection table = db.getCollection("user");
/**** Insert ****/
// create a document to store key and value
BasicDBObject document = new BasicDBObject();
document.put("name", "mkyong");
document.put("age", 30);
document.put("createdDate", new Date());
table.insert(document);
/**** Find and display ****/
BasicDBObject searchQuery = new BasicDBObject();
searchQuery.put("name", "mkyong");
DBCursor cursor = table.find(searchQuery);
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
/**** Update ****/
// search document where name="mkyong" and update it with new values
BasicDBObject query = new BasicDBObject();
query.put("name", "mkyong");
BasicDBObject newDocument = new BasicDBObject();
newDocument.put("name", "mkyong-updated");
BasicDBObject updateObj = new BasicDBObject();
updateObj.put("$set", newDocument);
table.update(query, updateObj);
/**** Find and display ****/
BasicDBObject searchQuery2
= new BasicDBObject().append("name", "mkyong-updated");
DBCursor cursor2 = table.find(searchQuery2);
while (cursor2.hasNext()) {
System.out.println(cursor2.next());
}
/**** Done ****/
System.out.println("Done");
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
}
}
}
控制臺輸入結果如下：
復制代碼 代碼如下:
db connection success！
db connection fail ！
{ "_id" : { "$oid" : "544073c4d58dfa6e469555ba"} , "name" : "mkyong" , "age" : 30 , "createdDate" : { "$date" : "2014-10-17T01:41:24.479Z"}}
{ "_id" : { "$oid" : "543e154bd58d704982fd38f0"} , "name" : "mkyong-updated" , "age" : 30 , "createdDate" : { "$date" : "2014-10-15T06:33:47.321Z"}}
{ "_id" : { "$oid" : "5440719dd58d08a207605c8e"} , "name" : "mkyong-updated" , "age" : 30 , "createdDate" : { "$date" : "2014-10-17T01:32:13.922Z"}}
{ "_id" : { "$oid" : "544073c4d58dfa6e469555ba"} , "name" : "mkyong-updated" , "age" : 30 , "createdDate" : { "$date" : "2014-10-17T01:41:24.479Z"}}
Done
源碼下載：http://xiazai.VeVB.COm/201503/other/mongodb_helloworld.zip
