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  • mongoDB用java实现增删改查

    package mongo;
    
    import java.net.UnknownHostException;
    
    import com.mongodb.BasicDBObject;
    import com.mongodb.DB;
    import com.mongodb.DBCollection;
    import com.mongodb.DBCursor;
    import com.mongodb.Mongo;
    import com.mongodb.MongoException;
    
    public class connection {
    	public static void main(String[] args){
    		try{
    			Mongo m = new Mongo("localhost", 27017);
    			DB db = m.getDB("company");
    			DBCollection collection = db.getCollection("employees");
    			BasicDBObject employee = new BasicDBObject();
    			employee.put("name", "Hannah");
    			employee.put("no", 2);
    			collection.insert(employee);
    			BasicDBObject searchEmployee = new BasicDBObject();
    			searchEmployee.put("no", 2);
    			DBCursor cursor = collection.find(searchEmployee);
    			while(cursor.hasNext()){
    				System.out.println(cursor.next());
    			}
    			System.out.println("The Search Query has Executed!"); 
    		}catch(UnknownHostException e){
    			e.printStackTrace();
    		}catch(MongoException e){
    			e.printStackTrace();
    		}
    	}
    }
    

     { "_id" : { "$oid" : "5454fa4458404d12637d418c"} , "name" : "Hannah" , "no" : 2}
    The Search Query has Executed!

    import java.net.UnknownHostException;  
    import java.util.Set;  
      
    import com.mongodb.BasicDBObject;  
    import com.mongodb.DB;  
    import com.mongodb.DBCollection;  
    import com.mongodb.DBCursor;  
    import com.mongodb.DBObject;  
    import com.mongodb.Mongo;  
    import com.mongodb.MongoException;  
      
    public class Test {  
      
        /** 
         * @author gaogao 
         * @param args 
         * @throws MongoException 
         * @throws UnknownHostException 
         */  
        public static void main(String[] args) throws UnknownHostException,  
                MongoException {  
            // TODO Auto-generated method stub  
            // 连接本地数据库  
            Mongo m = new Mongo();  
            // 创建名为new_test_db的数据库  
            DB db = m.getDB("new_test_db");  
            // 获取new_test_db中的集合(类似于获取关系数据库中的表)  
            Set<String> cols = db.getCollectionNames();  
            // 打印出new_test_db中的集合,这里应当为null  
            for (String s : cols) {  
                System.out.println(s);  
            }  
            // 创建一个叫做"new_test_col"的集合  
            DBCollection collection = db.getCollection("new_test_col");  
            // 初始化一个基本DB对象,最终插入数据库的就是这个DB对象  
            BasicDBObject obj = new BasicDBObject();  
            // 放入几个键值对  
            obj.put("from", "搞搞");  
            obj.put("to", "宝宝");  
            obj.put("subject", "狗子爱宝子");  
            //插入对象  
            collection.insert(obj);  
            //查看一条记录,findOne()=find().limit(1);  
            DBObject dbobj=collection.findOne();  
            //打印出刚才插入的数据  
            System.out.println(dbobj);  
            //现在我们来插入9条{ranking:i}的数据  
            for(int i=0;i<9;i++){  
                collection.insert(new BasicDBObject().append("ranking", i));  
            }  
            //打印集合中的数据总数,这里应当输出10  
            System.out.println(collection.getCount());  
            //下面我们来遍历集合,find()方法返回的是一个游标(cursor),这里的概念和关系数据库很相似  
            DBCursor cursor=collection.find();  
            //然后我们使用这个游标来遍历集合  
            while(cursor.hasNext()){  
                System.out.println(cursor.next());  
            }  
            //下面来看一些略复杂一点的查询技巧,第一个,简单的条件查询,查询ranking为1的记录  
            BasicDBObject query=new BasicDBObject();  
            query.put("ranking", 1);  
            cursor=collection.find(query);  
            while(cursor.hasNext()){  
                System.out.println(cursor.next());  
            }  
            //下面是更复杂的条件查询,查询ranking大于5小于9的记录  
            query=new BasicDBObject();  
            query.put("ranking", new BasicDBObject("$gt", 5).append("$lt", 9));  
            cursor=collection.find(query);  
            while(cursor.hasNext()){  
                System.out.println(cursor.next());  
            }  
            //最后删除我们的测试数据库  
            m.dropDatabase("new_test_db");  
        }  
    } 
    
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  • 原文地址:https://www.cnblogs.com/tuifeideyouran/p/4067954.html
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