MongoDB从不懂到装懂其三(Java操作MongoDB)

没什么好说的，和上一篇一样，只不过这一篇采用的语言环境是Java。

直接放代码吧，在代码中关于增删改查都做了详细的说明。

首先是一个MongoDB的帮助类，在这个类中定义了增删改查各种函数的实现，

然后是一个主函数入口，用来测试类的实现。

关于MongoDB Java 帮助类：

package com.blyang;import java.util.ArrayList;import java.util.List;import org.bson.Document;import org.bson.conversions.Bson;import com.mongodb.BasicDBObject;import com.mongodb.MongoClient;import com.mongodb.client.FindIterable;import com.mongodb.client.MongoCollection;import com.mongodb.client.MongoCursor;import com.mongodb.client.MongoDatabase;import com.mongodb.client.model.Filters;public class MongoDB {/** * 设置数据库连接地址 */private final String CONN_HOST = "127.0.0.1";/** * 设置数据库连接端口号 */private final int CONN_PORT = 27017;/** * MongoDB连接实例 */public MongoClient mongoClient = null;/** * MongoDB数据库实例 */public MongoDatabase mongoDatabase= null;/** * 构造方法 * 获取数据库实例 * @param DB_Name */public MongoDB(String DB_Name){this.mongoClient = new MongoClient(CONN_HOST, CONN_PORT);this.mongoDatabase = this.mongoClient.getDatabase(DB_Name);}/** * 创建数据库集合 * @param collName 数据库表名 */public boolean createCollection(String collName){try{this.mongoDatabase.createCollection(collName);}catch(Exception e){System.out.println(e.getMessage());return false;}return true;}/** * 获取数据库集合 * @param collName * @return */public MongoCollection<Document> getCollection(String collName){return this.mongoDatabase.getCollection(collName);}/** * 插入单个文档 * @param doc Bson文档 * @param collName 集合名称 */public void insert(Document doc, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);coll.insertOne(doc);}/** * 批量插入文档 * @param list List类型文档 * @param collName 集合名称 */public void insert(List<Document> list, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);coll.insertMany(list);}/** * 查找集合内所有Document * @param collName * @return */public List<Document> findAll(String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);List<Document> result = new ArrayList<Document>();FindIterable<Document> findIterable = coll.find();MongoCursor<Document> mongoCursor = findIterable.iterator();while(mongoCursor.hasNext()){result.add(mongoCursor.next());}return result;}/** * 指定条件查找 * @param query * @param collName * @return */public List<Document> findAll(BasicDBObject query, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);List<Document> result = new ArrayList<Document>();FindIterable<Document> findIterable = coll.find(query);MongoCursor<Document> mongoCursor = findIterable.iterator();while(mongoCursor.hasNext()){result.add(mongoCursor.next());}return result;}/** * 指定条件查找指定字段 * @param query * @param collName * @return */public List<Document> findAll(BasicDBObject query, BasicDBObject key, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);List<Document> result = new ArrayList<Document>();FindIterable<Document> findIterable = coll.find(query).projection(key);MongoCursor<Document> mongoCursor = findIterable.iterator();while(mongoCursor.hasNext()){result.add(mongoCursor.next());}return result;}/** * 查找一个 * @param query * @param collName * @return */public Document findOne(BasicDBObject query,String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);Document result = new Document();FindIterable<Document> findIterable = coll.find(query).limit(1);result = findIterable.iterator().next();return result;}/** * 删除集合中的所有数据 * @param collName */public void deleteAll(String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);BasicDBObject delDbo=new BasicDBObject();delDbo.append("_id", -1);coll.deleteMany(Filters.not(delDbo));}/** * 删除指定的所有数据 * @param b * @param collName */public void deleteAll(Bson b, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);coll.deleteMany(b);}/** * 删除指定的一条数据 * @param b * @param collName */public void deleteOne(Bson b, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);coll.deleteOne(b);}//collection.updateMany(Filters.eq("likes", 100), new Document("$set", new Document("likes",200)) );  /** * 按查询条件批量修改 * @param b * @param doc * @param collName */public void updateAll(Bson b, Document doc, String collName){MongoCollection<Document> coll = this.mongoDatabase.getCollection(collName);coll.updateMany(b, doc);}}

关于MongoDB Java测试实现：

package com.blyang;public class Mongo {      public static void main(String[] args) {    String collName = "hello";  MongoDB mongo = new MongoDB("blyang");    //创建  if(mongo.createCollection(collName)){  System.out.println("hello create success");  }  else{  System.out.println("create fail");  }    //  //单个插入//  Document docA = new Document();//  docA.append("key1", "val1");//  docA.append("key2", "val2");//  docA.append("key3", "val3");//  mongo.insert(docA, collName);    //  //批量插入//  List<Document> list = new ArrayList<Document>();//  for(int i=0; i<10; i++){//  Document doc = new Document();//  doc.append("key1", "val" + i);//  doc.append("key2", "val" + i);//  doc.append("key3", "val" + i);//  list.add(doc);//  }//  mongo.insert(list, collName);    //  //查询所有//  List<Document> findAll = mongo.findAll(collName);//  System.out.println(findAll.size());//  for(Document doc : findAll){//  System.out.println(doc.get("key3"));//  }    //  //指定条件查找全部//  BasicDBObject query =  new BasicDBObject();//  query.append("key3", "val99");//  List<Document> findAllB = mongo.findAll(query, collName);//  System.out.println(findAllB.size());//  for(Document doc : findAllB){//  System.out.println(doc.toString());//  }    //  //指定条件查找全部,返回指定字段//  BasicDBObject query =  new BasicDBObject();//  query.append("key3", "val99");//  BasicDBObject key = new BasicDBObject();//  key.append("key2",1);//  key.append("_id", 0);//  List<Document> findAllB = mongo.findAll(query,key, collName);//  System.out.println(findAllB.size());//  for(Document doc : findAllB){//  System.out.println(doc.toString());//  }    //  //指定条件查找一个//  BasicDBObject queryOne = new BasicDBObject();//  queryOne.append("key3", "val99");//  Document docOne = mongo.findOne(queryOne, collName);//  System.out.println(docOne);  //  //删除集合中的所有数据//  mongo.deleteAll(collName);    //  //删除集合中指定的所有数据//  Bson b = Filters.eq("key1", "val1");//  mongo.deleteAll(b,collName);  //  //删除指定的一个数据//  Bson b = Filters.eq("key1", "val1");//  mongo.deleteOne(b,collName);    //  //按查询条件批量更新//  Bson b = Filters.eq("key1", "val1");//  Document doc = new Document();//  doc.append("key1", "val100");//  Document docT = new Document("$set", doc);//  mongo.updateAll(b, docT, collName);    }  }

好啦，暂时就这样啦，需要调用的时候直接拷贝帮助类进入，然后调用帮助类中的增删改查的方法即可。