uas-eis/src/main/java/com/uas/eis/serviceImpl/Test.java

package com.uas.eis.serviceImpl;

import java.io.*;

/**
 * @author: zhouy
 * @date: 2021/11/26 16:10
 * @desc:
 */
public class Test {
    public static void main(String[] args) throws Exception {
        InputStream is=new FileInputStream("C:\\Picture\\a.txt");
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);
        String str = null;
        StringBuilder sb = new StringBuilder();
        while ((str = br.readLine()) != null) {
            System.out.println(str);
            sb.append(str);
        }
        saveToImgFile(sb.toString().toUpperCase(),"C:\\Picture\\p7.jpg");
     /*  DataOutputStream sos = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("C:\\\\Picture\\\\p5.jpg")));
       InputStream in  = new FileInputStream("C:\\Picture\\a.txt");
        int len = 0;
        byte[] b = new byte[1024];

        while ((len = in.read(b)) != -1) {
            System.out.println("write");
            sos.write(b,0,len);

        }

        sos.close();

        in.close();*/

    }
    public static void saveToImgFile(String src,String output){
        if(src==null||src.length()==0){
            return;
        }
        try{
            FileOutputStream out = new FileOutputStream(new File(output));
            byte[] bytes = src.getBytes();
            for(int i=0;i<bytes.length;i+=2){
                out.write(charToInt(bytes[i])*16+charToInt(bytes[i+1]));
            }
            out.close();
        }catch(Exception e){
            e.printStackTrace();
        }
    }
    private static int charToInt(byte ch){
        int val = 0;
        if(ch>=0x30&&ch<=0x39){
            val=ch-0x30;
        }else if(ch>=0x41&&ch<=0x46){
            val=ch-0x41+10;
        }
        return val;
    }
}