前言

公司项目中用到了实名认证此，采用的第三方平台。后端中用到的单项功能为身份证信息人像对比功能，在写demo的过程中发现，它们所要求的图片信息为base64编码格式。

一、代码

package com.bajiao.wyq.tools.chuanglan;import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.Base64;import javax.imageio.ImageIO;public class ConvertImage {/*** 图片转Base64字符串* @param imageFileName* @return*/public static String convertImageToBase64Str(String imageFileName) {ByteArrayOutputStream baos = null;try {//获取图片类型String suffix = imageFileName.substring(imageFileName.lastIndexOf(".") + 1);//构建文件File imageFile = new File(imageFileName);//通过ImageIO把文件读取成BufferedImage对象BufferedImage bufferedImage = ImageIO.read(imageFile);//构建字节数组输出流baos = new ByteArrayOutputStream();//写入流ImageIO.write(bufferedImage, suffix, baos);//通过字节数组流获取字节数组byte[] bytes = baos.toByteArray();//获取JDK8里的编码器Base64.Encoder转为base64字符return Base64.getEncoder().encodeToString(bytes);} catch (Exception e) {e.printStackTrace();} finally {try {if (baos != null) {baos.close();}} catch (IOException e) {e.printStackTrace();}}return null;}/*** Base64字符串转图片* @param base64String* @param imageFileName*/public static void convertBase64StrToImage(String base64String, String imageFileName) {ByteArrayInputStream bais = null;try {//获取图片类型String suffix = imageFileName.substring(imageFileName.lastIndexOf(".") + 1);//获取JDK8里的解码器Base64.Decoder,将base64字符串转为字节数组byte[] bytes = Base64.getDecoder().decode(base64String);//构建字节数组输入流bais = new ByteArrayInputStream(bytes);//通过ImageIO把字节数组输入流转为BufferedImageBufferedImage bufferedImage = ImageIO.read(bais);//构建文件File imageFile = new File(imageFileName);//写入生成文件ImageIO.write(bufferedImage, suffix, imageFile);} catch (Exception e) {e.printStackTrace();} finally {try {if (bais != null) {bais.close();}} catch (IOException e) {e.printStackTrace();}}}
}

二、测试

public static void main(String[] args) {System.out.println("----------------------------图片转Base64字符串---------------------------");//图片文件路径String imageFileName = "C:\\Users\\22.jpg";//图片转Base64字符串String base64Str = ConvertImage.convertImageToBase64Str(imageFileName);System.out.println(base64Str);System.out.println("----------------------------Base64字符串转图片---------------------------");//新文件路径String newFileName = "C:\\Users\\22.jpg";//Base64字符串转图片ConvertImage.convertBase64StrToImage(base64Str, newFileName);System.out.println("生成的文件的路径是："+newFileName);}