package com.what21.mongodb.demo; import java.util.ArrayList;import java.util.List;import java.util.Set;import java.util.regex.Pattern; import com.mongodb.BasicDBObject;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.DBObject;import com.mongodb.MongoClient;import com.mongodb.MongoClientOptions;import com.mongodb.MongoCredential;import com.mongodb.ServerAddress; public class OperateDemo2 {   /**   * @return   * @throws Exception   */  public static MongoClient getMongoClient()throws Exception{    try {      //===================================================//      List<ServerAddress> serverList = new ArrayList<ServerAddress>();      serverList.add(new ServerAddress("192.168.18.85", 27017));      //===================================================//      List<MongoCredential> mcList = new ArrayList<MongoCredential>();      String username = "root";      String database = "demo";      char[] password = "root123".toCharArray();      mcList.add(MongoCredential.createCredential(username, database,password));      //===================================================//      MongoClientOptions.Builder builder = MongoClientOptions.builder();      // 與目標數據庫能夠建立的最大connection數量為50       builder.connectionsPerHost(50);       // 如果當前所有的connection都在使用中，則每個connection上可以有50個線程排隊等待       builder.threadsAllowedToBlockForConnectionMultiplier(50);       // 一個線程訪問數據庫的時候，在成功獲取到一個可用數據庫連接之前的最長等待時間為2分鐘       // 這里比較危險，如果超過maxWaitTime都沒有獲取到這個連接的話，該線程就會拋出Exception       // 故這里設置的maxWaitTime應該足夠大，以免由于排隊線程過多造成的數據庫訪問失敗       builder.maxWaitTime(1000*60*2);       // 與數據庫建立連接的timeout設置為1分鐘       builder.connectTimeout(1000*60*1);        //===================================================//      MongoClientOptions mco = builder.build();       return new MongoClient(serverList, mcList, mco);    } catch (Exception e) {      throw e;    }  }     /**   * @param dbname   * @return   * @throws Exception   */  public static DB getDB(String dbname) throws Exception{    return getMongoClient().getDB(dbname);  }     /**   * @param db   */  public static void collections(DB db){    Set<String> colls = db.getCollectionNames();    for (String collName : colls) {      System.out.println(collName);    }  }     /**   * 記錄總數查詢   *    * @param db   * @param name   */  public static void count(DB db,String name){    DBCollection dbColl = db.getCollection(name);    int count = dbColl.find().count();    System.out.println("共有： " + count + "個");  }        /**   * 模糊查詢   *    * @param db   * @param name   */  public static void query(DB db,String name){    DBCollection dbColl = db.getCollection(name);    //完全匹配    //Pattern pattern = Pattern.compile("^name$", Pattern.CASE_INSENSITIVE);    //右匹配    //Pattern pattern = Pattern.compile("^.*name$", Pattern.CASE_INSENSITIVE);    //左匹配    //Pattern pattern = Pattern.compile("^name.*$", Pattern.CASE_INSENSITIVE);    //模糊匹配    Pattern pattern = Pattern.compile("^.*name8.*$", Pattern.CASE_INSENSITIVE);    BasicDBObject query = new BasicDBObject();    query.put("name",pattern);    BasicDBObject sort = new BasicDBObject();    // 1,表示正序； －1,表示倒序    sort.put("name",1);    DBCursor cur = dbColl.find(query).sort(sort);    int count = 0;    while (cur.hasNext()) {      DBObject obj = cur.next();      System.out.print("name=" + obj.get("name"));      System.out.print(",email=" + obj.get("email"));      System.out.println(",passwd=" + obj.get("passwd"));      count ++;    }    System.out.println("共有： " + count + "個");  }      /**   * 分頁查詢   *    * @param db   * @param name   * @param start   * @param pageSize   */  public static void page(DB db,String name,int start,int pageSize){    DBCollection dbColl = db.getCollection(name);    BasicDBObject sort = new BasicDBObject();    sort.put("name",1);    DBCursor cur = dbColl.find().sort(sort).skip(start).limit(pageSize);;    int count = 0;    while (cur.hasNext()) {      DBObject obj = cur.next();      System.out.print("name=" + obj.get("name"));      System.out.print(",email=" + obj.get("email"));      System.out.println(",passwd=" + obj.get("passwd"));      count ++;    }    System.out.println("共有： " + count + "個");  }  /**   * @param args   * @throws Exception    */  public static void main(String[] args) throws Exception {    DB db = getDB("demo");    collections(db);    String name = "users";    System.out.println("count()=================================================");    count(db,name);    System.out.println("query()=================================================");    query(db,name);    System.out.println("page()=================================================");    page(db,name,10, 10);  } }