Base64图片

Demo

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        boolean result = base64StrToImage(readTxtFile("C:/710207F5-510F-4afd-A0E3-4016663BAFEC.txt"), "C:/001.jpeg");
        System.out.println(result);
        boolean result2 = base64StrToImage(imageToBase64Str("C:/001.jpeg"),"C:/002.jpg");
        System.out.println(result2);
    }

    /**
     * 读取文件
     * @param filePath
     * @return
     */
    public static String readTxtFile(String filePath) {
        StringBuffer sbf = new StringBuffer();
        FileInputStream fis = null;
        InputStreamReader isr = null;
        BufferedReader br = null;
        try {
            //判断文件编码
            String encoding = resolveFileCharset(filePath);
            fis = new FileInputStream(filePath);
            isr = new InputStreamReader(fis, encoding);
            br = new BufferedReader(isr);
            String str;
            while ((str = br.readLine()) != null) {
                sbf.append(str);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                if (fis != null) {
                    fis.close();
                }
                if (isr != null) {
                    isr.close();
                }
                if (br != null) {
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                fis = null;
                isr = null;
                br = null;
            }
        }
        return sbf.toString();
    }

    /**
     * 判断文件编码
     *
     * @param fileName
     * @return
     */
    public static String resolveFileCharset(String fileName) {
        String fileCharCode = "GBK";
        FileInputStream fis = null;
        BufferedInputStream br = null;
        try {
            fis = new FileInputStream(fileName);
            br = new BufferedInputStream(fis);
            int p = (br.read() << 8) + br.read();
            //其中的
            switch (p) {
                case 0xefbb:
                    fileCharCode = "UTF-8";
                    break;
                case 0xfffe:
                    fileCharCode = "Unicode";
                    break;
                case 0xfeff:
                    fileCharCode = "UTF-16BE";
                    break;
                case 0x5c75:
                    fileCharCode = "ANSI|ASCII";
                    break;
                default:
                    fileCharCode = "GBK";
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (fis != null) {
                    fis.close();
                }
                if (br != null) {
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                fis = null;
                br = null;
            }
        }
        return fileCharCode;
    }

    /**
     * base64编码字符串转换为图片
     *
     * @param imgStr base64编码字符串
     * @param path   图片路径
     * @return
     */
    public static boolean base64StrToImage(String imgStr, String path) {
        if (imgStr == null) {
            return false;
        }
        BASE64Decoder decoder = new BASE64Decoder();
        try {
            //去除base64前缀
            String regEx = "data:image/\\w+;base64,";
            Pattern pattern = Pattern.compile(regEx);
            Matcher matcher = pattern.matcher(imgStr);
            imgStr = matcher.replaceAll("");
            // 解密
            byte[] b = decoder.decodeBuffer(imgStr);
            // 处理数据
            for (int i = 0; i < b.length; ++i) {
                if (b[i] < 0) {
                    b[i] += 256;
                }
            }
            //文件夹不存在则自动创建
            File tempFile = new File(path);
            if (!tempFile.getParentFile().exists()) {
                tempFile.getParentFile().mkdirs();
            }
            OutputStream out = new FileOutputStream(tempFile);
            out.write(b);
            out.flush();
            out.close();
            return true;
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * 图片转base64字符串
     *
     * @param imgFile 图片路径
     * @return
     */
    public static String imageToBase64Str(String imgFile) {
        InputStream is = null;
        byte[] data = null;
        try {
            is = new FileInputStream(imgFile);
            data = new byte[is.available()];
            is.read(data);
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 加密
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);
    }

}