2016年10月31日月曜日

Android FileWriter,FileReader

Android FileWriter,FileReader

文件的保存位置有要求
   String path ="/data/data/" + this.getPackageName() +"/demo.txt";



import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class MainActivity extends AppCompatActivity  {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        try {
            Test();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    protected void Test() throws IOException {
        final String tag = "testFile";
        String path ="/data/data/" + this.getPackageName() +"/demo.txt";
        FileWriter fileWriter = new FileWriter(path);

        for( int i = 0; i <102; i++){
            fileWriter.write(String.valueOf(i));
        }
        fileWriter.flush();
        fileWriter.close();

        FileReader fileReader = new FileReader(path);
        char[] buf = new char[24];
        int num;
        while(((num = fileReader.read(buf)) != 0)){
            System.out.println("---" + new String(buf,0,num));
        }
        fileReader.close();
    }
}


结果
com.example.java.m1031a I/System.out: ---012345678910111213141516
com.example.java.m1031a I/System.out: ---171819202122232425262728
com.example.java.m1031a I/System.out: ---293031323334353637383940
com.example.java.m1031a I/System.out: ---414243444546474849505152
com.example.java.m1031a I/System.out: ---535455565758596061626364
com.example.java.m1031a I/System.out: ---656667686970717273747576
com.example.java.m1031a I/System.out: ---777879808182838485868788
com.example.java.m1031a I/System.out: ---899091929394959697989910
com.example.java.m1031a I/System.out: ---0101





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