java version "1.7.0_45"
你好
我正在构造函数中初始化类方法.但是,新URL(uploadUrl)将在构造函数中引发异常.因此,如果发生这种情况,用户应该无法继续.由于构造函数无法返回任何内容,我想知道这是处理此问题的最佳方法吗？
非常感谢任何建议,
public class MultipleFileTransfer {
private static final String TAG = MultipartUtility.class.getSimpleName();
private DataOutputStream dataOutputStream;
private FileInputStream fileInputStream;
private HttpURLConnection httpURLConnection;
private URL url;
public MultipleFileTransfer(final String uploadUrl) {
dataOutputStream = null;
fileInputStream = null;
httpURLConnection = null;
try {
url = new URL(uploadUrl);
} catch (MalformedURLException e) {
Log.wtf(TAG,e.getMessage()); /* <-- How to handle a failure */
}
}
/* Factory method that initializes the class methods and returns the class object */
public static MultipleFileTransfer getInstance(final String uploadUrl) {
/* Check that a valid url has been entered correctly */
if(!URLUtil.isValidUrl(uploadUrl)) {
Log.wtf(TAG,"Invalid url: " + uploadUrl);
return null;
}
return new MultipleFileTransfer(uploadUrl);
}
}
解决方法
As the constructor cannot return anything,I am wondering that is the best way to handle this?
通常,允许异常直接传播给调用者,或者将其包装在您自己的更高级抽象异常中. (在你的情况下,只是让它直接看起来更合适.)
public MultipleFileTransfer(final String uploadUrl) throws MalformedURLException {
// -------------------------------------------------^
dataOutputStream = null;
fileInputStream = null;
httpURLConnection = null;
url = new URL(uploadUrl);
}
由于您的实例在没有URL的情况下没用,因此构造失败是有意义的.
或者,如果要在构造函数中记录它(但如果它正在传播,通常任何记录,如果适当的话将由调用者处理)：
// Logging and re-throwing,but probably not recommended
public MultipleFileTransfer(final String uploadUrl) throws MalformedURLException {
// -------------------------------------------------^
dataOutputStream = null;
fileInputStream = null;
httpURLConnection = null;
try {
url = new URL(uploadUrl);
} catch (MalformedURLException e) {
Log.wtf(TAG,e.getMessage());
throw e; // <== Rethrowing
}
}
