Java操作MongoDB模糊查询和分页查询

本文实例为大家分享了Java操作MongoDB模糊查询和分页查询，供大家参考，具体内容如下

模糊查询条件：
1、完全匹配
Pattern pattern = Pattern.compile("^name$", Pattern.CASE_INSENSITIVE);
2、右匹配
Pattern pattern = Pattern.compile("^.*name$", Pattern.CASE_INSENSITIVE);
3、左匹配
Pattern pattern = Pattern.compile("^name.*$", Pattern.CASE_INSENSITIVE);
4、模糊匹配
Pattern pattern = Pattern.compile("^.*name8.*$", Pattern.CASE_INSENSITIVE);
记录总数查询：
count()，返回查询总数。
查询记录排序：
BasicDBObject sort = new BasicDBObject();
sort.put("name",1);
1、表示正序；－1.表示倒序
分页查询：
skip()，跳过多少条记录
limit()，返回多少条记录

代码实例:

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();
      // 与目标数据库能够建立的最大connection数量为50
      builder.connectionsPerHost(50);
      // 如果当前所有的connection都在使用中，则每个connection上可以有50个线程排队等待
      builder.threadsAllowedToBlockForConnectionMultiplier(50);
      // 一个线程访问数据库的时候，在成功获取到一个可用数据库连接之前的最长等待时间为2分钟
      // 这里比较危险，如果超过maxWaitTime都没有获取到这个连接的话，该线程就会抛出Exception
      // 故这里设置的maxWaitTime应该足够大，以免由于排队线程过多造成的数据库访问失败
      builder.maxWaitTime(1000*60*2);
      // 与数据库建立连接的timeout设置为1分钟
      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);
    }
  }

  /**
   * 记录总数查询
   *
   * @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 + "个");
  }

  /**
   * 模糊查询
   *
   * @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 + "个");
  }

  /**
   * 分页查询
   *
   * @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 + "个");
  }
  /**
   * @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);
  }

}

以上就是Java操作MongoDB模糊查询和分页查询的实现代码，希望对大家的学习有所帮助。