Java单例模式下的MongoDB数据库操作工具类

<!-- MongoDB驱动 --><dependency>  <groupId>org.mongodb</groupId>  <artifactId>mongo-java-driver</artifactId>  <version>3.0.2</version></dependency>

package utils;import java.util.ArrayList;import java.util.List;import org.apache.commons.configuration.CompositeConfiguration;import org.apache.commons.configuration.ConfigurationException;import org.apache.commons.configuration.PropertiesConfiguration;import org.bson.Document;import org.bson.conversions.Bson;import org.bson.types.ObjectId;import com.mongodb.BasicDBObject;import com.mongodb.MongoClient;import com.mongodb.MongoClientOptions;import com.mongodb.MongoClientOptions.Builder;import com.mongodb.WriteConcern;import com.mongodb.client.MongoCollection;import com.mongodb.client.MongoCursor;import com.mongodb.client.MongoDatabase;import com.mongodb.client.MongoIterable;import com.mongodb.client.model.Filters;import com.mongodb.client.result.DeleteResult;/** * MongoDB工具类 Mongo实例代表了一个数据库连接池，即使在多线程的环境中，一个Mongo实例对我们来说已经足够了<br> * 注意Mongo已经实现了连接池，并且是线程安全的。 <br> * 设计为单例模式， 因 MongoDB的Java驱动是线程安全的，对于一般的应用，只要一个Mongo实例即可，<br> * Mongo有个内置的连接池（默认为10个） 对于有大量写和读的环境中，为了确保在一个Session中使用同一个DB时，<br> * DB和DBCollection是绝对线程安全的<br> * * @author zhoulingfei * @date 2015-5-29 上午11:49:49 * @version 0.0.0 * @Copyright (c)1997-2015 NavInfo Co.Ltd. All Rights Reserved. */public enum MongoDBUtil {  /**   * 定义一个枚举的元素，它代表此类的一个实例   */  instance;  private MongoClient mongoClient;  static {    System.out.println("===============MongoDBUtil初始化========================");    CompositeConfiguration config = new CompositeConfiguration();    try {      config.addConfiguration(new PropertiesConfiguration("mongodb.properties"));    } catch (ConfigurationException e) {      e.printStackTrace();    }    // 从配置文件中获取属性值    String ip = config.getString("host");    int port = config.getInt("port");    instance.mongoClient = new MongoClient(ip, port);    // or, to connect to a replica set, with auto-discovery of the primary, supply a seed list of members    // List<ServerAddress> listHost = Arrays.asList(new ServerAddress("localhost", 27017),new ServerAddress("localhost", 27018));    // instance.mongoClient = new MongoClient(listHost);    // 大部分用户使用mongodb都在安全内网下，但如果将mongodb设为安全验证模式，就需要在客户端提供用户名和密码：    // boolean auth = db.authenticate(myUserName, myPassword);    Builder options = new MongoClientOptions.Builder();    // options.autoConnectRetry(true);// 自动重连true    // options.maxAutoConnectRetryTime(10); // the maximum auto connect retry time    options.connectionsPerHost(300);// 连接池设置为300个连接,默认为100    options.connectTimeout(15000);// 连接超时，推荐>3000毫秒    options.maxWaitTime(5000); //    options.socketTimeout(0);// 套接字超时时间，0无限制    options.threadsAllowedToBlockForConnectionMultiplier(5000);// 线程队列数，如果连接线程排满了队列就会抛出“Out of semaphores to get db”错误。    options.writeConcern(WriteConcern.SAFE);//    options.build();  }  // ------------------------------------共用方法---------------------------------------------------  /**   * 获取DB实例 - 指定DB   *   * @param dbName   * @return   */  public MongoDatabase getDB(String dbName) {    if (dbName != null && !"".equals(dbName)) {      MongoDatabase database = mongoClient.getDatabase(dbName);      return database;    }    return null;  }  /**   * 获取collection对象 - 指定Collection   *   * @param collName   * @return   */  public MongoCollection<Document> getCollection(String dbName, String collName) {    if (null == collName || "".equals(collName)) {      return null;    }    if (null == dbName || "".equals(dbName)) {      return null;    }    MongoCollection<Document> collection = mongoClient.getDatabase(dbName).getCollection(collName);    return collection;  }  /**   * 查询DB下的所有表名   */  public List<String> getAllCollections(String dbName) {    MongoIterable<String> colls = getDB(dbName).listCollectionNames();    List<String> _list = new ArrayList<String>();    for (String s : colls) {      _list.add(s);    }    return _list;  }  /**   * 获取所有数据库名称列表   *   * @return   */  public MongoIterable<String> getAllDBNames() {    MongoIterable<String> s = mongoClient.listDatabaseNames();    return s;  }  /**   * 删除一个数据库   */  public void dropDB(String dbName) {    getDB(dbName).drop();  }  /**   * 查找对象 - 根据主键_id   *   * @param collection   * @param id   * @return   */  public Document findById(MongoCollection<Document> coll, String id) {    ObjectId _idobj = null;    try {      _idobj = new ObjectId(id);    } catch (Exception e) {      return null;    }    Document myDoc = coll.find(Filters.eq("_id", _idobj)).first();    return myDoc;  }  /** 统计数 */  public int getCount(MongoCollection<Document> coll) {    int count = (int) coll.count();    return count;  }  /** 条件查询 */  public MongoCursor<Document> find(MongoCollection<Document> coll, Bson filter) {    return coll.find(filter).iterator();  }  /** 分页查询 */  public MongoCursor<Document> findByPage(MongoCollection<Document> coll, Bson filter, int pageNo, int pageSize) {    Bson orderBy = new BasicDBObject("_id", 1);    return coll.find(filter).sort(orderBy).skip((pageNo - 1) * pageSize).limit(pageSize).iterator();  }  /**   * 通过ID删除   *   * @param coll   * @param id   * @return   */  public int deleteById(MongoCollection<Document> coll, String id) {    int count = 0;    ObjectId _id = null;    try {      _id = new ObjectId(id);    } catch (Exception e) {      return 0;    }    Bson filter = Filters.eq("_id", _id);    DeleteResult deleteResult = coll.deleteOne(filter);    count = (int) deleteResult.getDeletedCount();    return count;  }  /**   * FIXME   *   * @param coll   * @param id   * @param newdoc   * @return   */  public Document updateById(MongoCollection<Document> coll, String id, Document newdoc) {    ObjectId _idobj = null;    try {      _idobj = new ObjectId(id);    } catch (Exception e) {      return null;    }    Bson filter = Filters.eq("_id", _idobj);    // coll.replaceOne(filter, newdoc); // 完全替代    coll.updateOne(filter, new Document("$set", newdoc));    return newdoc;  }  public void dropCollection(String dbName, String collName) {    getDB(dbName).getCollection(collName).drop();  }  /**   * 关闭Mongodb   */  public void close() {    if (mongoClient != null) {      mongoClient.close();      mongoClient = null;    }  }  /**   * 测试入口   *   * @param args   */  public static void main(String[] args) {    String dbName = "GC_MAP_DISPLAY_DB";    String collName = "COMMUNITY_BJ";    MongoCollection<Document> coll = MongoDBUtil.instance.getCollection(dbName, collName);    // 插入多条    // for (int i = 1; i <= 4; i++) {    // Document doc = new Document();    // doc.put("name", "zhoulf");    // doc.put("school", "NEFU" + i);    // Document interests = new Document();    // interests.put("game", "game" + i);    // interests.put("ball", "ball" + i);    // doc.put("interests", interests);    // coll.insertOne(doc);    // }    // // 根据ID查询    // String id = "556925f34711371df0ddfd4b";    // Document doc = MongoDBUtil2.instance.findById(coll, id);    // System.out.println(doc);    // 查询多个    // MongoCursor<Document> cursor1 = coll.find(Filters.eq("name", "zhoulf")).iterator();    // while (cursor1.hasNext()) {    // org.bson.Document _doc = (Document) cursor1.next();    // System.out.println(_doc.toString());    // }    // cursor1.close();    // 查询多个    // MongoCursor<Person> cursor2 = coll.find(Person.class).iterator();    // 删除数据库    // MongoDBUtil2.instance.dropDB("testdb");    // 删除表    // MongoDBUtil2.instance.dropCollection(dbName, collName);    // 修改数据    // String id = "556949504711371c60601b5a";    // Document newdoc = new Document();    // newdoc.put("name", "时候");    // MongoDBUtil.instance.updateById(coll, id, newdoc);    // 统计表    // System.out.println(MongoDBUtil.instance.getCount(coll));    // 查询所有    Bson filter = Filters.eq("count", 0);    MongoDBUtil.instance.find(coll, filter);  }}