java中字符串Base64、16进制的转解码函数DatatypeConverter.printBase64Binary、parseBase64Binary用法

DatatypeConverter单元中封装了对base64编码的一些操作

printXXX 的函数就是encode
parseXXX 的函数就是decode

String printBase64Binary(byte[])   //就是将字节数组做base64编码
byte[] parseBase64Binary(String) //就是将Base64编码后的String还原成字节数组。

注意：传给printBase64Binary 的参数是 str.getBytes()，而不是 str 本身
示例：

    public static void main(String[] args) {
        String str = "This is Test String_123.AbcE";
        //BASE64编码与解码
        String encode = DatatypeConverter.printBase64Binary(str.getBytes());
        System.out.println(encode);
        byte[] decode= DatatypeConverter.parseBase64Binary(encode);
        System.out.println(new String(decode));
 
        //16进制编码与解码
        String encode1 = DatatypeConverter.printHexBinary(str.getBytes());
        System.out.println(encode1);
        byte[] decode1= DatatypeConverter.parseHexBinary(encode1);
        System.out.println(new String(decode1));
    }

效果：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import javax.xml.bind.DatatypeConverter;

public class Base64Utils {
    /**
     * 将文件转成base64 字符串
     * 
     * @param path文件路径
     * @return *
     * @throws Exception
     */

    public static String encodeBase64File(String path) throws Exception {
        File file = new File(path);
        FileInputStream inputFile = new FileInputStream(file);
        byte[] buffer = new byte[(int) file.length()];
        inputFile.read(buffer);
        inputFile.close();
        return DatatypeConverter.printBase64Binary(buffer);

    }

    /**
     * 将base64字符解码保存文件
     * 
     * @param base64Code
     * @param targetPath
     * @throws Exception
     */

    public static void decoderBase64File(String base64Code, String targetPath) throws Exception {
        byte[] buffer = DatatypeConverter.parseBase64Binary(base64Code);
        FileOutputStream out = new FileOutputStream(targetPath);
        out.write(buffer);
        out.close();

    }

    /**
     * 将base64字符保存文本文件
     * 
     * @param base64Code
     * @param targetPath
     * @throws Exception
     */

    public static void toFile(String base64Code, String targetPath) throws Exception {

        byte[] buffer = base64Code.getBytes();
        FileOutputStream out = new FileOutputStream(targetPath);
        out.write(buffer);
        out.close();
    }

    public static void main(String[] args) {
        try {
            String base64Code = encodeBase64File("C:/log.txt");
            System.out.println(base64Code);
            decoderBase64File(base64Code, "C:/log1.txt");
            toFile(base64Code, "C:\\three.txt");
        } catch (Exception e) {
            e.printStackTrace();

        }

    }
}