[英]ImageIO.write has invalid writer
Quarkus / JSF / Primefaces 项目。
我正在尝试将调整大小的图像转换回字节数组,但我一直为validWriter
获取false
,因此,返回的字节数组为空。
private byte[] createBytesFromImage(BufferedImage image, String contentType) {
ByteArrayOutputStream baosToReturn = new ByteArrayOutputStream();
try {
boolean validWriter = ImageIO.write(image, contentType, baosToReturn);
if (!validWriter) {
logger.error("Not a Valid Writer");
}
} catch (IOException e) {
baosToReturn = null;
logger.error("Error trying to convert image " + e);
e.printStackTrace();
}
return baosToReturn.toByteArray();
}
啊啊啊。
传递 contentType(来自上传的图像)不起作用。
你需要给图像一段文字,比如“png” ......
boolean validWriter = ImageIO.write(image, "png", baosToReturn);
与:
// https://stackoverflow.com/questions/67081086/imageio-write-has-invalid-writer
private byte[] createBytesFromImage(BufferedImage image, String contentType) {
ByteArrayOutputStream baosToReturn = new ByteArrayOutputStream();
String[] splitString = contentType.split("/");
if (splitString.length == 0) {
logger.error("++++++++++++++++++++++++++ content type cannot be split");
} else {
if (splitString.length != 2) {
logger.error("++++++++++++++++++++++++++ content type cannot be split to two parts (e.g. image and png)");
} else {
logger.info("contentType is split down to " + splitString[0] + " and " + splitString[1]);
if (!splitString[0].equalsIgnoreCase("image")) {
logger.error("++++++++++++++++++++++++++ content type first part is not image");
} else {
try {
boolean validWriter = ImageIO.write(image, splitString[1], baosToReturn);
if (!validWriter) {
logger.error("Could not find a Valid Image Writer");
}
} catch (IOException e) {
baosToReturn = null;
logger.error("Error trying to convert image " + e);
e.printStackTrace();
}
}
}
}
return baosToReturn.toByteArray();
}
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