字串陣列轉 Set

//String 陣列 --> Set<String>

public static Set<String> stringArrayToSet(String[] inputArray) throws Exception {

    Set<String> returnSet = new HashSet<String>();

    for (int i = 0; i < inputArray.length; i++) {

        returnSet.add(inputArray[i]);

    }

    return returnSet;

}

JAVA 讀檔並 return List

private static List<String> readFileToStringList(String filePath) {

    List<String> returnList = new ArrayList<String>();

    try {

        FileReader fr = new FileReader(filePath);

        BufferedReader br = new BufferedReader(fr);

        String line;

        while ((line = br.readLine()) != null) {

            System.out.println(line);

            returnList.add(line);

        }

    } catch (Exception e) {

        e.printStackTrace();

    }

    return returnList;

}

JAVA 遞迴走訪目錄

private void retrievalFolder(String path) throws Exception {

    try {

        File main = new File(path);

        if (main.isDirectory()) {

            String[] filename = main.list();

            for (int i = 0; i < filename.length; i++) {

                File sub = new File(main.getAbsoluteFile() + File.separator + filename[i]);

                if (sub.isDirectory()) {

                    this.retrievalFolder(main.getAbsoluteFile() + File.separator + filename[i]);

                } else {

                    //TODO

                }

            }

        } else {

            //TODO

        }

    } finally {

        //TODO

    }

}

可參考
列出目錄中(包含子目錄)之所有檔案

SQL: 找出某個欄位重複出現的資料

select
    [Column_Name],
    count(*)
from
    [Table_Name] 
group by
    [Column_Name] having count(*) > 1

其中[Column_Name]若是該 Table 中應為 Unique 之欄位，且該欄位未設定為 unique 時，可利用此方法找出重複出現的資料

列出目錄中(包含子目錄)之所有檔案

private void listFilesInDirectoryRecursively(String path) {

    File main = new File(path);

    if (main.isDirectory()) {

        String[] filename = main.list();

        for (int i = 0; i < filename.length; i++) {

            File sub = new File(main.getAbsoluteFile() + File.separator + filename[i]);

            if (sub.isDirectory()) {

                this.listFilesInDirectoryRecursively(main.getAbsoluteFile() + File.separator + filename[i]);

            } else {

                System.out.println(sub.getAbsoluteFile());

            }

        }

    } else {

        System.out.println(main.getAbsoluteFile());

    }

}