• mongodb- Java API 查询操作


    package com.x.mongodb;

    import java.net.UnknownHostException;
    import java.util.Collection;
    import java.util.HashMap;
    import java.util.Iterator;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.Set;

    import org.bson.types.BasicBSONList;
    import org.bson.types.ObjectId;

    import com.mongodb.BasicDBObject;
    import com.mongodb.DB;
    import com.mongodb.DBCollection;
    import com.mongodb.DBCursor;
    import com.mongodb.DBObject;
    import com.mongodb.Mongo;
    import com.mongodb.MongoException;

    /**
    * 查询</br>
    * : $in { "name1" : { "$in" : [ "zhou28-1" , "zhou29"]}}</br>
    * : $nin { "age" : { "$nin" : [ 1 , 2]}}
    * : $or { "$or" : [ { "name1" : { "$in" : [ "zhou28-1" , "zhou29"]}}]}</br>
    * : $or and{ "$or" : [ { "name1" : { "$in" : [ "zhou28-1" , "zhou29"]}}] , "name2" : "zhou"}</br>
    * : 范围查询 { "age" : { "$gte" : 2 , "$lte" : 21}}</br>
    * : $ne { "age" : { "$ne" : 23}}</br>
    * : $lt { "age" : { "$lt" : 23}}
    * @author <a href="http://blog.csdn.net/java2000_wl">java2000_wl</a>
    * @version <b>1.0</b>
    */
    public final class MongoDBUtil {

    private static final String HOST = "127.0.0.1";

    private static final String dbName = "test";

    private static Mongo mongo;

    private static DB db;

    static {
    try {
    mongo = new Mongo(HOST);
    db = mongo.getDB(dbName);
    // db.authenticate(username, passwd)
    } catch (UnknownHostException e) {
    e.printStackTrace();
    } catch (MongoException e) {
    e.printStackTrace();
    }
    }

    private MongoDBUtil() {
    }

    /**
    * 判断集合是否存在
    * <br>------------------------------<br>
    * @param collectionName
    * @return
    */
    public static boolean collectionExists(String collectionName) {
    return db.collectionExists(collectionName);
    }

    /**
    * 查询单个,按主键查询
    * <br>------------------------------<br>
    * @param id
    * @param collectionName
    */
    public static void findById(String id, String collectionName) {
    Map<String, Object> map = new HashMap<String, Object>();
    map.put("_id", new ObjectId(id));
    findOne(map, collectionName);
    }

    /**
    * 查询单个
    * <br>------------------------------<br>
    * @param map
    * @param collectionName
    */
    public static void findOne(Map<String, Object> map, String collectionName) {
    DBObject dbObject = getMapped(map);
    DBObject object = getCollection(collectionName).findOne(dbObject);
    print(object);
    }

    /**
    * 查询全部
    * <br>------------------------------<br>
    * @param cursor
    * @param collectionName
    */
    public static void findAll(CursorObject cursor, String collectionName) {
    find(new HashMap<String, Object>(), cursor, collectionName);
    }

    /**
    * count
    * <br>------------------------------<br>
    * @param map
    * @param collectionName
    * @return
    */
    public static long count(Map<String, Object> map, String collectionName) {
    DBObject dbObject = getMapped(map);
    return getCollection(collectionName).count(dbObject);

    }

    /**
    * 按条件查询 </br>
    * 支持skip,limit,sort
    * <br>------------------------------<br>
    * @param map
    * @param cursor
    * @param collectionName
    */
    public static void find(Map<String, Object> map, CursorObject cursor, String collectionName) {
    DBObject dbObject = getMapped(map);
    find(dbObject, cursor, collectionName);
    }

    /**
    * 查询
    * <br>------------------------------<br>
    * @param dbObject
    * @param cursor
    * @param collectionName
    */
    public static void find(DBObject dbObject, final CursorObject cursor, String collectionName) {
    CursorPreparer cursorPreparer = cursor == null ? null : new CursorPreparer() {
    public DBCursor prepare(DBCursor dbCursor) {
    if (cursor == null) {
    return dbCursor;
    }
    if (cursor.getLimit() <= 0 && cursor.getSkip() <=0 && cursor.getSortObject() == null) {
    return dbCursor;
    }
    DBCursor cursorToUse = dbCursor;
    if (cursor.getSkip() > 0) {
    cursorToUse = cursorToUse.skip(cursor.getSkip());
    }
    if (cursor.getLimit() > 0) {
    cursorToUse = cursorToUse.limit(cursor.getLimit());
    }
    if (cursor.getSortObject() != null) {
    cursorToUse = cursorToUse.sort(cursor.getSortObject());
    }
    return cursorToUse;
    }
    };
    find(dbObject, cursor, cursorPreparer, collectionName);
    }

    /**
    * 查询
    * <br>------------------------------<br>
    * @param dbObject
    * @param cursor
    * @param cursorPreparer
    * @param collectionName
    */
    public static void find(DBObject dbObject, CursorObject cursor, CursorPreparer cursorPreparer, String collectionName) {
    DBCursor dbCursor = getCollection(collectionName).find(dbObject);
    if (cursorPreparer != null) {
    dbCursor = cursorPreparer.prepare(dbCursor);
    }
    Iterator<DBObject> iterator = dbCursor.iterator();
    while (iterator.hasNext()) {
    print(iterator.next());
    }
    }

    /**
    * 获取集合(表)
    * <br>------------------------------<br>
    * @param collectionName
    * @return
    */
    public static DBCollection getCollection(String collectionName) {
    return db.getCollection(collectionName);
    }

    /**
    * 获取所有集合名称
    * <br>------------------------------<br>
    * @return
    */
    public static Set<String> getCollection() {
    return db.getCollectionNames();
    }

    /**
    * 创建集合
    * <br>------------------------------<br>
    * @param collectionName
    * @param options
    */
    public static void createCollection(String collectionName, DBObject options) {
    db.createCollection(collectionName, options);
    }

    /**
    * 删除
    * <br>------------------------------<br>
    * @param collectionName
    */
    public static void dropCollection(String collectionName) {
    DBCollection collection = getCollection(collectionName);
    collection.drop();
    }

    /**
    *
    * <br>------------------------------<br>
    * @param map
    * @return
    */
    private static DBObject getMapped(Map<String, Object> map) {
    DBObject dbObject = new BasicDBObject();
    Iterator<Entry<String, Object>> iterable = map.entrySet().iterator();
    while (iterable.hasNext()) {
    Entry<String, Object> entry = iterable.next();
    Object value = entry.getValue();
    String key = entry.getKey();
    if (key.startsWith("$") && value instanceof Map) {
    BasicBSONList basicBSONList = new BasicBSONList();
    Map<String, Object> conditionsMap = ((Map)value);
    Set<String> keys = conditionsMap.keySet();
    for (String k : keys) {
    Object conditionsValue = conditionsMap.get(k);
    if (conditionsValue instanceof Collection) {
    conditionsValue = convertArray(conditionsValue);
    }
    DBObject dbObject2 = new BasicDBObject(k, conditionsValue);
    basicBSONList.add(dbObject2);
    }
    value = basicBSONList;
    } else if (value instanceof Collection) {
    value = convertArray(value);
    } else if (!key.startsWith("$") && value instanceof Map) {
    value = getMapped(((Map)value));
    }
    dbObject.put(key, value);
    }
    return dbObject;
    }

    private static Object[] convertArray(Object value) {
    Object[] values = ((Collection)value).toArray();
    return values;
    }

    private static void print(DBObject object) {
    Set<String> keySet = object.keySet();
    for (String key : keySet) {
    print(object.get(key));
    }
    }

    private static void print(Object object) {
    System.out.println(object.toString());
    }
    }

    package com.x.mongodb;

    import com.mongodb.DBObject;

    /**
    * 分页,排序对象
    * @author <a href="http://blog.csdn.net/java2000_wl">java2000_wl</a>
    * @version <b>1.0</b>
    */
    public class CursorObject {

    private int skip;

    private int limit;

    private Sort sort;

    public CursorObject skip(int skip) {
    this.skip = skip;
    return this;
    }

    public CursorObject limit(int limit) {
    this.limit = limit;
    return this;
    }

    public int getSkip() {
    return skip;
    }

    public int getLimit() {
    return limit;
    }

    public Sort sort() {
    if (this.sort == null) {
    this.sort = new Sort();
    }
    return this.sort;
    }

    public DBObject getSortObject() {
    if (this.sort == null) {
    return null;
    }
    return this.sort.getSortObject();
    }
    }

  • 相关阅读:
    oracle归档日志增长过快处理方法
    Oracle“死锁”模拟
    Oracle 手工清除回滚段的几种方法
    Oracle 一次 锁表 处理小记
    Oracle中如何判断一个字符串是否含有汉字
    机房收费系统验收总结
    hdu 4747 Mex (线段树)
    Java 5 的新标准语法和用法详解集锦
    java类加载器行为[笔记]
    poj1330Nearest Common Ancestors(LCA小结)
  • 原文地址:https://www.cnblogs.com/divenswu/p/3517172.html
Copyright © 2020-2023  润新知