Java MongoDB 实例HelloWorld
一个简单的入门例子，演示连接客户端，怎样创建一个数据库、表，怎样实现数据的增、删、改、查等操作

1. 在Eclipse中建立一个Maven工程


2. 获取Mongo Java Driver

<dependency>
  		<groupId>org.mongodb</groupId>
  		<artifactId>mongo-java-driver</artifactId>
  		<version>2.11.0</version>
  	</dependency>

如果不使用Maven工程，可以从https://github.com/mongodb/mongo-java-driver/downloads获取jar包

3. HelloWorld

import java.net.UnknownHostException;
import java.util.Date;
import java.util.List;
import java.util.Set;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.MongoClient;
import com.mongodb.MongoException;

public class MongoDBExample {
	public static void main(String[] args) {
		try {
			// 1. 连接到MongoDB服务器
			MongoClient mongo = new MongoClient("localhost", 27017);
			// 2. 获取数据库
			// 如果指定的数据库[yourdb]不存在，MongoDB将会新建一个数据库
			DB db = mongo.getDB("yourdb");
			//显示所有数据库
			List<String> dbs = mongo.getDatabaseNames();
			for(String database: dbs){
				System.out.println("db: "+database);
			}
			// 3. 获取一个表
			// 如果表不存在，MongoDB将会新建一个
			DBCollection table = db.getCollection("users");
			
			//显示选择的数据库中所有表
			Set<String> tables = db.getCollectionNames();
			for(String coll : tables){
				System.out.println("table:　"+coll);
			}

			// 新增一条记录
			BasicDBObject document = new BasicDBObject();
			document.put("username", "yourname");
			document.put("password", "123456");
			document.put("age", 22);
			document.put("createdDate", new Date());
			table.insert(document);

			// 查找并显示一条记录
			BasicDBObject searchQuery = new BasicDBObject();
			searchQuery.put("username", "yourname");
			DBCursor cursor = table.find(searchQuery);
			while (cursor.hasNext()) {
				System.out.println(cursor.next());
			}

			//更新一条记录
			BasicDBObject query = new BasicDBObject();
			query.put("username", "yourname");

			BasicDBObject newDocument = new BasicDBObject();
			newDocument.put("username", "yourname-update");

			BasicDBObject updateObj = new BasicDBObject();
			updateObj.put("$set", newDocument);

			table.update(query, updateObj);

			//查找更新后的记录
			BasicDBObject searchQuery2 = new BasicDBObject().append("username", "yourname-update");
			DBCursor cursor2 = table.find(searchQuery2);
			while (cursor2.hasNext()) {
				System.out.println(cursor2.next());
			}
			System.out.println("End");
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (MongoException e) {
			e.printStackTrace();
		}
	}
}

4. 运行结果


5. mongo 客户端


6. MongoDB客户端工具RockMongo界面