Java操作MongoDB模糊查询和分页查询

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

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);
    }
 
}