我正在尝试使用 jQuery 插件crop.js 裁剪/调整用户个人资料图像的大小，该插件通过 Ajax 将用户图像作为 Base64 发送到我的控制器：
$.ajax({
type: "post",
dataType: "json",
url: "${g.createLink(controller: 'personalDetail', action:'uploadUserImage')}",
data: { avatar: canvas.toDataURL() }
});
但我无法将此 Base64 字符串解码为图像：
'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...=='
如何将 Base64 字符串保存为服务器上的图像？
在服务器中，执行如下操作：
假设
String data = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...=='
然后：
String base64Image = data.split(",")[1];
byte[] imageBytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(base64Image);
然后你可以用这样的字节做任何你喜欢的事情：
BufferedImage img = ImageIO.read(new ByteArrayInputStream(imageBytes));
这假设了一些事情，即您知道输出文件名是什么并且您的数据以字符串形式出现。我确信您可以修改以下内容来满足您的需求：
// Needed Imports
import java.io.ByteArrayInputStream;
import sun.misc.BASE64Decoder;
def sourceData = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...==';
// tokenize the data
def parts = sourceData.tokenize(",");
def imageString = parts[1];
// create a buffered image
BufferedImage image = null;
byte[] imageByte;
BASE64Decoder decoder = new BASE64Decoder();
imageByte = decoder.decodeBuffer(imageString);
ByteArrayInputStream bis = new ByteArrayInputStream(imageByte);
image = ImageIO.read(bis);
bis.close();
// write the image to a file
File outputfile = new File("image.png");
ImageIO.write(image, "png", outputfile);
请注意，这只是所涉及部件的示例。我根本没有优化这段代码，它是我凭空想象出来的。
ImageIO.write()BufferedOutputStream这是代码：
import javax.xml.bind.DatatypeConverter;
import java.io.*;
public class ImageTest {
public static void main(String[] args) {
String base64String = "data:image/jpeg;base64,iVBORw0KGgoAAAANSUhEUgAAAHkAAAB5C...";
String[] strings = base64String.split(",");
String extension;
switch (strings[0]) {//check image's extension
case "data:image/jpeg;base64":
extension = "jpeg";
break;
case "data:image/png;base64":
extension = "png";
break;
default://should write cases for more images types
extension = "jpg";
break;
}
//convert base64 string to binary data
byte[] data = DatatypeConverter.parseBase64Binary(strings[1]);
String path = "C:\\Users\\Ene\\Desktop\\test_image." + extension;
File file = new File(path);
try (OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(file))) {
outputStream.write(data);
} catch (IOException e) {
e.printStackTrace();
}
}
}
简单就是：
import java.util.Base64;
解码：
byte[] image = Base64.getDecoder().decode(base64string);
编码：
String text = Base64.getEncoder().encodeToString(imageData);
服务器端将文件/图像编码为 base64String 可供客户端使用
public Optional<String> InputStreamToBase64(Optional<InputStream> inputStream) throws IOException{
if (inputStream.isPresent()) {
ByteArrayOutputStream output = new ByteArrayOutputStream();
FileCopyUtils.copy(inputStream.get(), output);
//TODO retrieve content type from file, & replace png below with it
return Optional.ofNullable("data:image/png;base64," + DatatypeConverter.printBase64Binary(output.toByteArray()));
}
return Optional.empty();
}
服务器端base64图像/文件解码器
public Optional<InputStream> Base64InputStream(Optional<String> base64String)throws IOException {
if (base64String.isPresent()) {
return Optional.ofNullable(new ByteArrayInputStream(DatatypeConverter.parseBase64Binary(base64String.get())));
}
return Optional.empty();
}
public Optional<String> InputStreamToBase64(Optional<InputStream> inputStream) throws IOException{
if (inputStream.isPresent()) {
ByteArrayOutputStream outpString base64Image = data.split(",")[1];
byte[] imageBytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(base64Image);
然后你可以用这样的字节做任何你喜欢的事情：
BufferedImage img = ImageIO.read(new ByteArrayInputStream(imageBytes));ut = new ByteArrayOutputStream();
FileCopyUtils.copy(inputStream.get(), output);
//TODO retrieve content type from file, & replace png below with it
return Optional.ofNullable("data:image/png;base64," + DatatypeConverter.printBase64Binary(output.toByteArray()));
}
return Optional.empty();
嗨，这是我的解决方案
Javascript代码
var base64before = document.querySelector('img').src;
var base64 = base64before.replace(/^data:image\/(png|jpg);base64,/, "");
var httpPost = new XMLHttpRequest();
var path = "your url";
var data = JSON.stringify(base64);
httpPost.open("POST", path, false);
// Set the content type of the request to json since that's what's being sent
httpPost.setRequestHeader('Content-Type', 'application/json');
httpPost.send(data);
这是我的 Java 代码。
public void saveImage(InputStream imageStream){
InputStream inStream = imageStream;
try {
String dataString = convertStreamToString(inStream);
byte[] imageBytes = javax.xml.bind.DatatypeConverter.parseBase64Binary(dataString);
BufferedImage image = ImageIO.read(new ByteArrayInputStream(imageBytes));
// write the image to a file
File outputfile = new File("/Users/paul/Desktop/testkey/myImage.png");
ImageIO.write(image, "png", outputfile);
}catch(Exception e) {
System.out.println(e.getStackTrace());
}
}
static String convertStreamToString(java.io.InputStream is) {
java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
return s.hasNext() ? s.next() : "";
}
这是 Ayano 的出色答案，但在 Clojure 中：
(:import (java.awt.image BufferedImage)
(javax.xml.bind DatatypeConverter)
(java.io File BufferedOutputStream FileOutputStream))
(defn write-svg-encountered-image [svg-img-data base-filename]
(let [[meta img-data] (str/split svg-img-data #",")
extension (case meta
"data:image/jpeg;base64" ".jpeg"
"data:image/png;base64" ".png"
(throw (Error. (format "Unrecognised image metadata in SVG:" meta))))
path (str base-filename extension)
file (File. path)
data-bytes (DatatypeConverter/parseBase64Binary img-data)
os (BufferedOutputStream. (FileOutputStream. file))]
(.write os data-bytes)))
String[] strings = expense.getAttchBase64().split(",");
String extension;
switch (strings[0]) {//check image's extension
case "data:image/jpeg;base64":
extension = "jpeg";
break;
case "data:image/png;base64":
extension = "png";
break;
case "data:application/pdf;base64":
extension = "pdf";
break;
case "data:application/vnd.openxmlformats-officedocument.wordprocessingml.document;base64":
extension = "docx";
break;
default://should write cases for more images types
extension = "jpg";
break;
}
//convert base64 string to binary data
byte[] data = DatatypeConverter.parseBase64Binary(strings[1]);
String fileName = UUID.randomUUID().toString();
String path = "C:\\floridatrading\\" + fileName + "." + extension;
File file = new File(path);
try (OutputStream outputStream = new BufferedOutputStream(new FileOutputStream(file))) {
outputStream.write(data);
} catch (IOException e) {
e.printStackTrace();
}
如果您需要添加任何新类型，只需将其添加到 switch 中。