IO简化概述II

第二部分：

import java.io.*;

public class IO {
    
    public static void main(String[] args) throws IOException {
        //OutputStream：
        //把数据内容传入到硬盘文件
        //比较常用的FileOutputStream
//        FileOutputStream fileOutputStream = new FileOutputStream("/Users/christopoher/Desktop/竞赛/Morgan Stanley Presentation", true);
//        byte[] b = {65,66,67,68,69,70,71,72,73};
//        //or
//        b = "65,66,67,68,69,70,71,72,73".getBytes();
//        fileOutputStream.write(b);
//        fileOutputStream.write(b, 0,4);
//        fileOutputStream.close();
//        System.out.println("已经写出");

        //InputStream
        //再将刚刚output文件内容重新读取或者到输入到我们的内存中
        FileInputStream fileInputStream = new FileInputStream("/Users/christopoher/Desktop/demoFile");
        int es = fileInputStream.available();
        for (int i = 0; i < es; i++) {
            byte bi = (byte) fileInputStream.read(); // 一字节一字节读
            System.out.println((char) bi);
        }
        fileInputStream.close();

        // 一次读一组
        // 建立在已经创建了的file情况下
        FileInputStream fileInputStream2 = new FileInputStream("/Users/christopoher/Desktop/demoFile");
        byte[] bytes = new byte[10]; // 每次读10个一组
        int len = fileInputStream2.read(bytes); // 一组字节地读，得到读了多少个字节
        System.out.println(new String(bytes, 0, len));
        len = fileInputStream2.read(bytes);// 一组字节地读，得到读了多少个字节
        System.out.println(new String(bytes, 0, len));
        len = fileInputStream2.read(bytes);// 一组字节地读，得到读了多少个字节
        System.out.println(new String(bytes, 0, len));
        fileInputStream.close();

    }


}

-------------------------------

下面拓展一下非常基础的，运用SimpleDateFormat类去收集异常日志

import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;


public class ExceptionCollector {
    public static void main(String[] args) throws IOException {
        try {
            String s = null;
            s.toString();
        }catch (Exception e){
            PrintWriter printWriter = new PrintWriter("/Users/christopoher/Desktop/bug.txt");
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
            printWriter.println(sdf.format(new Date()));
            e.printStackTrace(printWriter);
            printWriter.close();
        }
    }
}