小编use*_*645的帖子

以下代码是我试图识别内部存储中是否存在文件的方法MODE_PRIVATE.

public boolean isset(String filename){
    FileInputStream fos = null;
    try {
       fos = openFileInput(filename);
       //fos = openFileInput(getFilesDir()+"/"+filename);
       if (fos != null) {
         return true;
       }else{
         return false;
       }
    } catch (FileNotFoundException e) {
        return false;
    }

    //File file=new File(mContext.getFilesDir(),filename);

    //boolean exists = fos.exists();
    }

但是,它进入异常并且不继续使用代码.它没有回报.为什么？

我有一个名为students.json的文件,如下所示:

{"uid":1,"name":"Michael","sid":1}
{"uid":2,"name":"Andy", "age":30,"sid":1}
{"uid":3,"name":"Jsaxsustin", "age":19,"sid":1}
{"uid":4,"name":"Andasxsay", "age":30,"sid":2}
{"uid":5,"name":"Jusewedtin", "age":19,"sid":1}
{"uid":6,"name":"Anwereddy", "age":30,"sid":3}
{"uid":7,"name":"Justdwedwein", "age":19,"sid":2}
{"uid":8,"name":"Andwedewy", "age":30,"sid":1}
{"uid":9,"name":"Justidedwn", "age":19,"sid":1}
{"uid":10,"name":"Anddwdey", "age":30,"sid":3}
{"uid":11,"name":"Michael","sid":1}
{"uid":12,"name":"Andy", "age":30,"sid":1}
{"uid":13,"name":"Jsaxsustin", "age":19,"sid":1}
{"uid":14,"name":"Andasxsay", "age":30,"sid":2}
{"uid":15,"name":"Jusewedtin", "age":19,"sid":1}
{"uid":16,"name":"Anwereddy", "age":30,"sid":3}
{"uid":17,"name":"Justdwedwein", "age":19,"sid":2}
{"uid":18,"name":"Andwe2fr3fdewy", "age":30,"sid":1}
{"uid":19,"name":"Justide4y45y54dwn", "age":19,"sid":1}
{"uid":20,"name":"Anddwd45y45yey", "age":30,"sid":3}
{"uid":21,"name":"Justdw45y45yedin", "age":19,"sid":1}
{"uid":22,"name":"An45y45ydy", "age":30,"sid":1}
{"uid":23,"name":"Jsaxsus4y54ytin", "age":19,"sid":1}
{"uid":24,"name":"Andas45y4y5xsay", "age":30,"sid":2}
{"uid":25,"name":"Jusewe4y5dtin", "age":19,"sid":1}
{"uid":26,"name":"Anwere45y45yddy", "age":30,"sid":3}
{"uid":27,"name":"Justdwe4y4y5dwein", "age":19,"sid":2}
{"uid":28,"name":"Andwede45ywy", "age":30,"sid":1}
{"uid":29,"name":"Justided45y45wn", "age":19,"sid":1}
{"uid":30,"name":"Anddwde4t4y", "age":30,"sid":3}
{"uid":31,"name":"Mich4y554ael","sid":1}
{"uid":32,"name":"An45ydy", "age":30,"sid":1}
{"uid":33,"name":"Jsaxsudfsstin", "age":19,"sid":1}
{"uid":34,"name":"Andasxssdfdsay", "age":30,"sid":2}
{"uid":35,"name":"Jusewedtsdfdsin", "age":19,"sid":1}
{"uid":36,"name":"Anweredsfdsdy", "age":30,"sid":3}
{"uid":37,"name":"Justdwedfsdwein", "age":19,"sid":2}
{"uid":38,"name":"Andwedewy", "age":30,"sid":1}
{"uid":39,"name":"Jdsfdsfustidedwn", "age":19,"sid":1}
{"uid":40,"name":"Ansdfdsey", "age":30,"sid":3}
{"uid":41,"name":"Jussdsdtdwedin", "age":19,"sid":1} …

我有一个脚本,看起来像下面的例子.我有一个字母偏移,我需要打印我用偏移量计算的字母.我不知道如何使用ksh阅读那封信.

我期望的答案是LETTER_OFFSET(1)= a,LETTER_OFFSET(2)= v,LETTER_OFFSET(3)= c等.我在循环内计算了它的偏移量.

#!/bin/ksh
#         1    2  3  4  5  6  7 8  9 10  11 12
LETTERS=" a    v  c  d  g  r  g s  s a   g   f"
LETTER_OFFSET="3";
Letter=$(echo $LETTERS | awk '{print $((1 * $$LETTER_OFFSET )) }')