FileInputStream，FileOutputStream-检查文件中的特定值/行/字符串

Question

I consulted this community already a few times, but nevertheless it seems I'm still to unexperienced to solve my problems on my own.

My latest problem is the following:

I have a file, created in the private storage of the app (unrooted device). I´m able to write to it, and to read from it. BUT: I do not know, how i add additional information in my file ( I think another FOS will easily add the array at the end of the first, but am not sure), and I have no idea, how i can have a look for a specific eg String.

public static Runnable cfgsetlanecount(int l1, int l2, int l3, int l4,
        int l5, int l6, int l7, int l8, Context context)

        throws IOException {
    System.out.println("" + l1 + l2+ l3+l4+l5+l6+l7+l8);
    FileOutputStream fos = context
            .openFileOutput(cfg, Context.MODE_PRIVATE);
    String lanecount = "lanecount: " + (Integer.valueOf(l1).toString())
            + "" + (Integer.valueOf(l2).toString()) + ""
            + (Integer.valueOf(l3).toString()) + ""
            + (Integer.valueOf(l4).toString()) + "" + l5 + "" + l6 + ""
            + l7 + "" + l8;
    byte buf[] = lanecount.getBytes(); 
    fos.write(buf);
    fos.close();
    cfggetlanecount();
    return null;
}

public static Runnable cfggetlanecount() throws IOException {
    String collected =  null;
    FileInputStream fis = context.openFileInput(cfg);
    byte input[] = new byte [fis.available()];
    while (fis.read(input)!=-1){
        collected = new String (input);

        System.out.println(collected);
    }fis.close();
    return null;

}

This is the code of what I have done till now. I want to add a time String with the value 12:00 and read them form different methods. The lanecount String has got the values 10101010 I just want this values, by saying search for String lanecount: and get the 12:00 by saying search for String time:

EDIT:

First of all should this lines be added to my file. This is what it should look like:

line1: lanecount: 10001000

line2: time: 12:00

line3: timex: 05:00

line4: anyword: fhfbjklös

line5: Stopbyte: 0x28

. . .

and now I want a method, that is able to take out the value of Keyword timex, or another one, that can read the lanecount. And maybe one that can get the value of Stopbyte.

Then I need a method, which is able to EDIT the value of Keyword time.

Answer 1

Based on the file content you described, it sounds like a natural properties file:

# This is a comment:
lanecount=10001000
time=12:00
timex=05:00
anyword=fhfbjklös
Stopbyte=0x28
... ...

Use java.util.Properties , it does all dirty work for you:

# Write properties to private storage:
FileOutputStream fos = context.openFileOutput(cfg, Context.MODE_PRIVATE);
Properties props = new Properties();
props.setProperty("lanecount", "10001000");
props.setProperty("time", "12:00");
prop.store(fos, "This is a comment"); // store() is threadsafe
fos.close();

... ...

# Read properties from private storage: 
FileInputStream fis = context.openFileInput(cfg);
Properties props = new Properties();
props.load(fis); // load() is threadsafe
fis.close();
String lanecount = props.getProperty("lanecount");
String time = props.getProperty("time");

I don't know your requirements, as an alternative, you can load/store your configurations from SharedPreferences instead of app's private storage:

# Write properties to shared preferences:
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
SharedPreferences.Editor editor = prefs.edit();
editor.putString("lanecount", "10001000");
editor.putString("time", "12:00");
editor.commit();

... ...

# Read properties from shared preferences:
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
String lanecount = prefs.getString("lanecount", "defauleValue");
String time = prefs.getString("time", "defauleValue");

Hope this helps.

Answer 2

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

import android.content.Context;
import android.os.Environment;

import com.bowltec.own.OwnClass;

public class Config_cbt extends OwnClass{
    static String cfg = "config.cbt";
    static int coll;
    static Properties props;

    public static void createcfg() throws FileNotFoundException, IOException {
        String packageName = acti.getPackageName();
        String path = Environment.getExternalStorageDirectory()
                .getAbsolutePath() + "/Android/data/" + packageName + "/files/";
        new File(path).mkdirs();
        props = new Properties();
    }

    public static void cfgset(String key, String val)
            throws IOException {
        FileOutputStream fos = acti.openFileOutput(cfg, Context.MODE_PRIVATE);
            props.setProperty(key, val);
            props.store(fos, "...");
    }

    public static int cfgget(String tocollect) throws IOException {

        FileInputStream fis = context.openFileInput(cfg);
        props.load(fis);
        fis.close();
        String collected = props.getProperty(tocollect, "0");
        coll = Integer.valueOf(collected);
        return coll;
    }
}

This is how i have it now. This works perfect. It`s for all those having problems on the same issue. Pls feel free to use.

acti is declared in my OwnClass using protected static Activity acti; and acti = this;