Java Operation MongoDB Fuzzy query and paging query _java

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Fuzzy query conditions:
1. Perfect Match
Pattern pattern = pattern.compile ("^name$", pattern.case_insensitive);
2, right matching
Pattern pattern = pattern.compile ("^.*name$", pattern.case_insensitive);
3, left match
Pattern pattern = pattern.compile ("^name.*$", pattern.case_insensitive);
4, Fuzzy matching
Pattern pattern = pattern.compile ("^.*name8.*$", pattern.case_insensitive);
Total Records query:
Count (), returns the total number of queries.
Query Record sorting:
Basicdbobject sort = new Basicdbobject ();
Sort.put ("name", 1);
1, positive sequence;-1. Indicates reverse order
Paging Query:
Skip (), how many records are skipped
Limit (), how many records are returned

Code instance:

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<Mongo
      Credential> ();
      String username = "root"; String Database = "DemO ";
      char[] Password = "root123". ToCharArray ();
      Mclist.add (mongocredential.createcredential (username, database,password)); ===================================================//Mongoclientoptions.builder Builder =
      Mongoclientoptions.builder (); 
      The maximum number of connection that can be established with the target database is builder.connectionsperhost (50); 
      If all current connection are in use, 50 threads can be queued for builder.threadsallowedtoblockforconnectionmultiplier (50) on each connection; When a thread accesses a database, the maximum wait time before a successful access to an available database connection is 2 minutes or more dangerous, if more than Maxwaittime did not get this connection, the thread will throw exception/ 
      The Maxwaittime set here should be large enough to prevent database access failures due to excessive queuing of threads builder.maxwaittime (1000*60*2);  
      The timeout with the database connection is set to 1 minutes 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 Getmongo
  Client (). GETDB (dbname); }/** * @param db */public static void collections (DB db) {set<string> colls = Db.getcollectionna
    Mes ();
    for (String collname:colls) {System.out.println (collname);
    /** * Records Totals query * * @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 ("total:" + Count + "a"); /** * Fuzzy Query * * @param DB * @param name */public static void query (DB db,string name) {D
    Bcollection dbcoll = db.getcollection (name);
    Perfectly matched//pattern pattern = pattern.compile ("^name$", pattern.case_insensitive);
    Right matching//pattern pattern = pattern.compile ("^.*name$", pattern.case_insensitive); Left match//pattern pattern = Pattern.compiLe ("^name.*$", pattern.case_insensitive);
    Fuzzy matching pattern pattern = pattern.compile ("^.*name8.*$", pattern.case_insensitive);
    Basicdbobject query = new Basicdbobject ();
    Query.put ("name", pattern);
    Basicdbobject sort = new Basicdbobject ();
    1, indicating positive sequence, 1, which indicates reverse 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 ("total:" + Count + "a");  /** * Paging Query * * @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 ("total:" + Count + "a"); /** * @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);
 }
 
}

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