如何读取java文件中的特定行并打印出...？ [英] how to read a specific line in .java file and prints out ...?

问题描述

我创建一个项目中，我需要阅读从java文件关键字启动特定行。

i am creating a project in which i need to read a specific line starting from a keyword in .java file .

我将要读的.java的文件：

i will have to read .java files for :

Intent myIntent = new Intent(StudentMap.this, StudentPref.class);
StudentMap.this.startActivity(myIntent);

我怎么会在code随时随地阅读这两条线。我应该要设置的正则表达式这一点，但怎么样？

how will i read these two lines anywhere in the code . should i have to set regex for this but how ?

我使用的：

public void onClick(View v) {

    TextView responseText = (TextView) findViewById(R.id.responseText);
    String myData = "";
String test = "Intent ";
   // String name="";
    switch (v.getId()) {
        case R.id.getExternalStorage:
            try {
                FileInputStream fis = new FileInputStream(myExternalFile);
                DataInputStream in = new DataInputStream(fis);
                BufferedReader br = new BufferedReader(new InputStreamReader(in));
                String strLine;

                while ((strLine = br.readLine()) != null){
                    myData = myData + strLine;



                    if (strLine.equals(test)) {

                        tv1.setText(tv1.getText() + strLine + "\n");
                    }
                    else{
                        tv1.setText(tv1.getText() + "nakaam" + "\n");

                    }

                }
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

            responseText.setText("MySampleFile.java data retrieved from external Storage...");

            break;

    }

    tv1.setText(tv1.getText() + myData + "\n"+"\n"+"\n"+"end");

    //tv1.setText(tv1.getText() + strLine + "\n");


}

据我所知意图关键字是每个文件静态的，所以我能得到​​这样的意图，但如何阅读这条线和大型文件只剩下一行一行的开始..？

as far my knowledge Intent keyword is static in every file so i can get the start of line like "Intent" but how to read this line and the next line only from large file..?

推荐答案

如果您想在关键字意图开始您的字符串，并阅读后线的数量，你可以做这样的事情：

If you want to start your String at the Keyword Intent, and read a Number of Lines after that, you can do something like this:

try {
    BufferedReader br = new BufferedReader(new FileReader(file));
    int remainingLines = 0;
    String stringYouAreLookingFor = "";
    for(String line; (line = br.readLine()) != null; ) {
        if (line.startsWith("Intent")) {
            remainingLines = <Number of Lines you want to read after keyword>;
            stringYouAreLookingFor += line
        } else if (remainingLines > 0) {
            remainingLines--;
            stringYouAreLookingFor += line
        }    
    }
}

我想这应该给你如何找到你要查找的字符串的想法。

I guess this should give you an idea on how to search the String you are looking for.

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