Java操作MongoDB模糊查询和分页查询

 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 serverList = new ArrayList(); serverList.add(new ServerAddress("192.168.18.85", 27017)); //===================================================// List mcList = new ArrayList(); 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 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); } }