MongoDB程序開發之使用Java驅動

記錄一下使用mongodb java driver來訪問數據庫的一些總結。

 

 主要是由createMongoInstance()方法完成初始化工作。

protected static final Mongo mongoInstance = createMongoInstance();

private static Mongo createMongoInstance() {
        MongoOptions mo = new MongoOptions();
        mo.socketKeepAlive=true;
        mo.autoConnectRetry = true;
        mo.maxAutoConnectRetryTime=10;
        mo.connectionsPerHost = 40;
        mo.connectTimeout = 20 * 1000;
        mo.socketTimeout = 60 * 1000;
        try {
            if (DatabaseProject.DB_CONFIG.containsKey("mongodb.ips")) {
                return new Mongo(getServerAddrsFromConf("mongodb"),mo);
            }
            return new Mongo(new ServerAddress(DatabaseProject.DB_CONFIG.getString("mongodb.ip"), DatabaseProject.DB_CONFIG.getInt("mongodb.port")),mo);

        } catch (Throwable e) {
            DatabaseProject.LOGGER.error("Failed to init mongodb", e);
            throw new ExceptionInInitializerError(e);
        }
    }

  其中有一些數據庫配置直接寫在配置文件裏了，在MongoJavaDriverDAO中初始化一部分數據：

 

public void insertCollData(){
        //如果該collection不存在則會自動創建
        DBCollection parentcoll = getCollection("ParentColl");
        DBCollection childcoll = getCollection("ChildColl");
        for(int i=0;i<1000;i++){
            DBObject document = new BasicDBObject();
            document.put("intData", 1000+i);
            document.put("longData", System.currentTimeMillis());
            document.put("strData", UUID.randomUUID().toString());
            document.put("doubleData", 1.123+i);
            document.put("createDate", new Date());
            document.put("booleanData", true);
            DBObject innerDoc = new BasicDBObject();
            innerDoc.put("innertype", "string");
            innerDoc.put("innerContent", "string"+i);
            document.put("documentData", innerDoc);
            parentcoll.insert(document);
            DBObject childDocument = new BasicDBObject();
            childDocument.put("parentId", document.get("_id"));
            childDocument.put("createDate", new Date());
            List list = new ArrayList();
            list.add("str" + i%10);
            list.add("str" + i%20);
            list.add(new BasicDBObject("arr"+(i%10),(i%10)));
            list.add(new BasicDBObject("arr"+(i%20),(i%20)));
            childDocument.put("arrays",list);
            childcoll.insert(childDocument);
        }
        System.out.println("ParentColl Count:"+parentcoll.count());
        System.out.println("ChildColl Count:"+childcoll.count());
    }

 其中getCollection方法會獲取集合，不存在的話會自動創建一個。getCollection方法如下：

 

public static DBCollection getCollection(String collectionName){
    return getDB().getCollection(collectionName);
}

 現在創建了2個集合ParentColl、ChildColl，並初始化了數據。

查詢相關方法：

 

/**
     * 查詢全部數據
     */
    public void findColl(){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find();
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
        System.out.println("Count:"+coll.count());
    }

    /**
     * 根據ObjectId查詢
     */
    public void findById(String id){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find(new BasicDBObject("_id", new ObjectId(id)));//直接用string查不出來
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * And多條件查詢
     */
    public void findByAndQuery(int intData,long longData){
        coll = getCollection("ParentColl");
        BasicDBObject query = new BasicDBObject();
        query.put("intData", intData);
        query.put("longData", longData);
        System.out.println(coll.findOne(query));
    }

    /**
     * OR多條件查詢
     */
    public void findByORQuery(int lte,int gt,long longData){
        coll = getCollection("ParentColl");
        BasicDBObject query=new BasicDBObject();
        BasicDBObject longdata = new BasicDBObject("longData", longData);
        BasicDBObject intdata = new BasicDBObject("intData", new BasicDBObject().append("$gt", gt).append("$lte",lte));
        BasicDBList cond=new BasicDBList();
        cond.add(longdata);
        cond.add(intdata);
        query.put("$or", cond);
        DBCursor cur = coll.find(query);
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * IN查詢
     */
    public void findByINQuery(int value1,int value2){
        coll = getCollection("ParentColl");
        BasicDBObject query=new BasicDBObject();
        BasicDBList cond=new BasicDBList();
        cond.add(value1);
        cond.add(value2);
        query.put("intData",new BasicDBObject("$in", cond));
        DBCursor cur = coll.find(query);
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * NOT查詢
     */
    public void findByNotQuery(int value1,int value2){
        coll = getCollection("ParentColl");
        BasicDBObject query=new BasicDBObject();
        BasicDBList cond=new BasicDBList();
        cond.add(value1);
        cond.add(value2);
        query.put("intData",new BasicDBObject("$nin", cond));
        System.out.println("Count:"+coll.find(query).count());
    }

    /**
     * 獲取結果集第一條
     */
    public void fetchFirstQuery(int value1,int value2){
        coll = getCollection("ParentColl");
        BasicDBList cond = new BasicDBList();
        cond.add(value1);
        cond.add(value2);
        BasicDBObject query = new BasicDBObject().append("intData",new BasicDBObject("$nin",cond));
        System.out.println(coll.findOne(query));
    }

    /**
     * 查詢文檔部分列
     */
    public void querySomeKey(){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find(new BasicDBObject(),new BasicDBObject("intData",true));
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * 查詢內嵌文檔
     */
    public void queryInnerDocument(){
        coll = getCollection("ParentColl");
        BasicDBObject map = new BasicDBObject();
        map.put("innertype","string");
        map.put("innerContent","string0");
        DBCursor cur = coll.find(new BasicDBObject("documentData",map));
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * 查詢內嵌部分文檔
     */
    public void querySubInnerDocument(){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find(new BasicDBObject("documentData.innerContent","string0"));
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * 查詢分頁文檔
     */
    public void queryByPage(int skipNum,int pageNum){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find().skip(skipNum).limit(pageNum);
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * 查詢文檔某列是否存在
     */
    public void queryExists(){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find(new BasicDBObject("longData",new BasicDBObject("$exists",true)));
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * 查詢文檔排序
     */
    public void sortDocument(){
        coll = getCollection("ParentColl");
        DBCursor cur = coll.find().sort(new BasicDBObject("intData",-1));//1:asc / -1:desc
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

補充distinct查詢：

/**
* 獲取根據某元素做distinct查詢.
*/
  public void distinctKey(){
coll = getCollection("ParentColl");
List<String> list = coll.distinct("documentData.innertype");
for(String str:list){
    System.out.println(str);
}
  }

不難發現主要用到BasicDBObject、BasicDBList、DBCursor這三個類。BasicDBObject好比一個map，好比使用json查詢中的{} 。BasicDBList是個list，用於or，nin等條件查詢。DBCursor用於遍歷結果集。其實只要將對應的json查詢使用這3個類轉化一下，就能寫出對應的java代碼了。

 

更新相關：

 

/**
     * 更新文檔1
     */
    public void updateDocument(){
        DB db = getDB();
        //由於mongodb中使用連接池的原因,getLastError()需要再次從連接池中獲取連接.
        //保證update操作和getLastError()使用同一個連接.
        db.requestStart();
        coll = db.getCollection("ParentColl");
        WriteResult result = coll.update(new BasicDBObject("intData",1100),new BasicDBObject("$set", new BasicDBObject("booleanData",false)));
        System.out.println("update count:"+result.getN());
        if(result.getLastError().ok()){//獲取上次操作結果是否有錯誤.
            System.out.println("update document success.");
        }else{
            System.out.println(result.getLastError().getErrorMessage());
        }
        db.requestDone();
    }

    /**
     * 更新文檔2
     */
    public void updateMultiDocument(){
        DB db = getDB();
        db.requestStart();
        coll = db.getCollection("ParentColl");
        //第三個參數:如果沒有該文檔是否創建,第四個參數:是否更新全部匹配條件的文檔.
        WriteResult result = coll.update(new BasicDBObject("booleanData",false),new BasicDBObject("$set", new BasicDBObject("booleanData",true)),false,true);
        System.out.println("update count:"+result.getN());
        if(result.getLastError().ok()){//獲取上次操作結果是否有錯誤.
            System.out.println("update document success.");
        }else{
            System.out.println(result.getLastError().getErrorMessage());
        }
        db.requestDone();
    }

 注意requestStart、requestDone方法保證使用同一個數據庫連接。WriteResult記錄更新結果。 

 

索引相關：

 

/**
     * 創建唯一索引
     */
    public void createIndexes(){
        coll = getCollection("ParentColl");
        BasicDBObject index = new BasicDBObject();
        index.put("intData",1);//1:asc / -1:desc
        index.put("unique",true);//唯一索引
        coll.createIndex(index);
    }

    /**
     * 查詢索引信息
     */
    public void getIndexes(){
        coll = getCollection("ParentColl");
        List<DBObject> indexInfo = coll.getIndexInfo();
        System.out.println(indexInfo);
    }

    /**
     * 刪除索引信息
     */
    public void dropIndexes(){
        coll = getCollection("ParentColl");
        //刪除的索引必須跟創建的索引名稱\排序\是否唯一都相同才能刪除
        BasicDBObject index = new BasicDBObject();
        index.put("intData",1);
        index.put("unique",true);
        coll.dropIndex(index);
    }

 對於文檔可能還會對數組操作：

 

/**
     * 取出文檔中的數組
     */
    public void queryArray(){
        coll = getCollection("ChildColl");
        DBCursor cur = coll.find(new BasicDBObject(),new BasicDBObject("arrays",1));
        while(cur.hasNext()){
            BasicDBObject bo = (BasicDBObject)cur.next();
            List<BasicDBObject> list = (List<BasicDBObject>)bo.get("arrays");
            System.out.println(list.toString());
        }
    }

    /**
     * 查詢數組內是否包含某元素
     */
    public void queryElementInArray(){
        coll = getCollection("ChildColl");
        BasicDBObject query = new BasicDBObject();
        BasicDBObject obj = new BasicDBObject();
        obj.put("arr0",0);
        query.put("arrays", new BasicDBObject("$elemMatch",obj));
        DBCursor cur = coll.find(query);
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * 數組內包含元素的值
     */
    public void queryElementArray(){
        coll = getCollection("ChildColl");
        BasicDBObject obj = new BasicDBObject();
        obj.put("arrays", "str0");
        obj.put("arrays.arr0",0);
        obj.put("arrays.arr10",10);
        DBCursor cur = coll.find(obj);
        while(cur.hasNext()){
            System.out.println(cur.next());
        }
    }

    /**
     * push(pushAll) array element
     */
    public void pushElementInArray(String _id){
        DB db = getDB();
        db.requestStart();
        coll = getCollection("ChildColl");
        //WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$push",new BasicDBObject("arrays",new BasicDBObject("arr99","99"))));
        List<BasicDBObject> list=new ArrayList<BasicDBObject>();
        list.add(new BasicDBObject("arr99",99));
        list.add(new BasicDBObject("arr100",100));
        WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pushAll",new BasicDBObject("arrays",list)));
        System.out.println("update count:"+result.getN());
        if(result.getLastError().ok()){
            System.out.println("update document success.");
        }else{
            System.out.println(result.getLastError().getErrorMessage());
        }
        db.requestDone();
    }

    /**
     * pull(pullAll) array element
     */
    public void pullElementInArray(String _id){
        DB db = getDB();
        db.requestStart();
        coll = getCollection("ChildColl");
        List<BasicDBObject> list=new ArrayList<BasicDBObject>();
        list.add(new BasicDBObject("arr99",99));
        list.add(new BasicDBObject("arr100",100));
        //WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pull",new BasicDBObject("arrays",new BasicDBObject("arr100",100))));
        WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pullAll",new BasicDBObject("arrays",list)));
        System.out.println("update count:"+result.getN());
        db.requestDone();
    }

    /**
     * pop array element(1,last;-1,first)
     */
    public void popElementInArray(String _id){
        coll = getCollection("ChildColl");
        WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pop",new BasicDBObject("arrays",-1)));//1,last;-1,first
        System.out.println("update count:"+result.getN());
    }

    /**
     * addToSet And Each array element
     */
    public void addToSetAndEachElementInArray(String _id){
        coll = getCollection("ChildColl");
        List list = new ArrayList();
        list.add("str0");
        list.add("str1");
        list.add(new BasicDBObject("arr99",99));
        WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$addToSet",new BasicDBObject("arrays",new BasicDBObject("$each",list))));//1,last;-1,first
        System.out.println("update count:"+result.getN());
    }

/**
     * 按數組位置更新文檔(查詢條件需要包含更新內容，$爲數組位置佔位符，只更新匹配到的第一個文檔.)
     */
    public void updatePositionInArray(String _id){
        coll = getCollection("ChildColl");
        WriteResult result = coll.update(new BasicDBObject("arrays.arr0", 100),new BasicDBObject("$set",new BasicDBObject("arrays.$.arr0",101)));
        System.out.println("update count:"+result.getN());
    }

   以上都是一些基本的查詢、更新操作，當然還有一些如map reduce和關聯查詢等複雜的方法，我將另寫一篇blog總結一下。