mongodb缩短java源代码

Question

下面的代码打算在我的项目中创建一个搜索列。但我高度怀疑代码的效率，因为它相当长。是否有可能通过减少代码行数来执行与代码相关的任务

package kelas_java;
public class searchingDariSemuaKolom {

public static void main(String[] args) {
    BasicDBObject sortOrder = new BasicDBObject();
    MongoClient mongoClient;
    DB db;

    DBCollection table, table2;
    DBCursor cur = null, cur2 = null;
    try {
        mongoClient = new MongoClient("localhost", 27017);
        db = mongoClient.getDB("face");
        boolean auth = db.authenticate("aku", "kamu".toCharArray());
        Pattern regex = Pattern.compile("1");
//start1
table = db.getCollection("titles");
        DBObject clause1 = new BasicDBObject("link", regex);
        DBObject clause2 = new BasicDBObject("title", regex);
        DBObject clause3 = new BasicDBObject("body", regex);
        DBObject clause4 = new BasicDBObject("date", regex);
        BasicDBList or1 = new BasicDBList();
        or1.add(clause1);
        or1.add(clause2);
        or1.add(clause3);
        or1.add(clause4);
        DBObject query = new BasicDBObject("$or", or1);
        cur = table.find(query);
        while (cur.hasNext()) {
            System.out.println(cur.next().get("title"));
        }
//end1
//start2
table2 = db.getCollection("news");
        DBObject clause5 = new BasicDBObject("link", regex);
        DBObject clause6 = new BasicDBObject("title", regex);
        DBObject clause7 = new BasicDBObject("body", regex);
        DBObject clause8 = new BasicDBObject("date", regex);
        BasicDBList or2 = new BasicDBList();
        or2.add(clause1);
        or2.add(clause2);
        or2.add(clause3);
        or2.add(clause4);
        DBObject query2 = new BasicDBObject("$or", or2);
        cur2 = table2.find(query2);
        while (cur2.hasNext()) {
            System.out.println(cur2.next().get("title"));
        }
//end2
 } catch (Exception ex) {

    } finally {
        cur.close();
        cur2.close();
    }
}
}  

Answer 1

编辑：拉赫马特比我抢先一步，但我想我还是发帖为好

你的问题是冗长而不是效率

只有在有不可预测的失败原因的情况下，才能尝试/抓住机会。然后只放可能会失败的那一行，而不是所有的代码。然后，在“catch”中，指定预期的错误，以及要对此执行的操作

阅读文件，分析里面的信息，等等，都是为了抓住机会

就我个人而言，我不喜欢创建额外的变量，因为它们不会被多次使用或有助于澄清。但这取决于你

还有，你从来没用过巫师。而且类名应该大写，不过没什么大不了的

package kelas_java;
public class SearchingDariSemuaKolom {

    public static void main(String[] args) {

       // Not sure which of these need to be in here
       try {
           MongoClient mongoClient = new MongoClient("localhost", 27017);
           DB db = mongoClient.getDB("face");
           boolean auth = db.authenticate("aku", "kamu".toCharArray());
       } catch (Exception ex) {
           System.out.println("Error: " + ex.getMessage());
       }

        Pattern regex = Pattern.compile("1");

        String[] stuffToAdd = {"link", "title", "body", "date"};

        BasicDBList or1 = method2(db, "titles", stuffToAdd);
        BasicDBList or2 = method2(db, "news", stuffToAdd);
    }

    public BasicDbList method2(DB db, String str, String[] stuffToAdd) {
       BasicDBList or = createDbList(stuffToAdd);
       DBCollection table = db.getCollection(str);
       DBCursor cur = table.find(new BasicDBObject("$or", or));
       while (cur.hasNext())
           System.out.println(cur.next().get(str));
       cur.close();
       return or;
    }

    public BasicDbList createDbList(String[] toAdd) {
        BasicDbList or = new BasicDbList();
        for(String newString : toAdd)
            or.add(new BasicDbObject(newString, regex));
        return or;
    }

}

Answer 2

始终使用方法缩短代码。当您需要多次执行相同的工作时，只需调用您的方法并向其传递真参数

下面是对代码的一些更改，我删除了从数据库打印一些数据的重复代码，并创建了一个名为doPrint的方法，该方法包含四个参数

• 字符串数组命名键，它的值将被分配给BasicDBObject
• 将分配给BasicDBObject的值
• 您与之连接的数据库
• 以及要从中读取数据的集合（表）名称

然后，您只需调用doPrint

doPrint(keys , regex , db , "titles");

希望能有帮助

package kelas_java;
public class searchingDariSemuaKolom {

    static void doPrint(String keys, Object value, DB db, String collectionName) {
        BasicDBList or = new BasicDBList();
        for (String key : keys) {
            or.add(new BasicDBObject(key, value));
        }
        DBObject query = new BasicDBObject("$or", or);
        DBCollection table = db.getCollection(collectionName);

        try {
            DBCursor cur = table.find(query);
            while (cur.hasNext()) {
                System.out.println(cur.next().get("title"));
            }
        } catch (MongoException e) {
            System.out.println("Error: "+e.getMessage());
        } finally {
            cur.close();
        }
    }
    public static void main(String[] args) {
        BasicDBObject sortOrder = new BasicDBObject();
        MongoClient mongoClient;
        DB db;

        String strs[] = {
            "link", 
            "title",
            "body", 
            "date", 
        };
        try {
            mongoClient = new MongoClient("localhost", 27017);
            db = mongoClient.getDB("face");
            boolean auth = db.authenticate("aku", "kamu".toCharArray());
            Pattern regex = Pattern.compile("1");

            //start1
            doPrint(keys , regex , db , "titles");
            //start2
            doPrint(keys , regex , db , "news");
        } catch (Exception e) {
            System.out.println("Error: "+e.getMessage());
        }
    }
}