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Java 8: Lambda-Streams,Filter by Method with Exception13个
我有下面的代码.
我有下面的代码.
private static void readStreamWithjava8() {
Stream<String> lines = null;
try {
lines = Files.lines(Paths.get("b.txt"),StandardCharsets.UTF_8);
lines.forEachOrdered(line -> process(line));
} catch (IOException e) {
e.printstacktrace();
} finally {
if (lines != null) {
lines.close();
}
}
}
private static void process(String line) throws MyException {
// Some process here throws the MyException
}
这里我的进程(String line)方法抛出已检查的异常,我从lambda中调用该方法.此时需要从readStreamWithjava8()方法抛出MyException而不抛出RuntimeException.
我怎么能用java8做到这一点？
解决方法
简短的回答是,你做不到.这是因为forEachOrdered接受了Consumer,并且未声明Consumer.accept会抛出任何异常.
解决方法是做类似的事情
List<MyException> caughtExceptions = new ArrayList<>();
lines.forEachOrdered(line -> {
try {
process(line);
} catch (MyException e) {
caughtExceptions.add(e);
}
});
if (caughtExceptions.size() > 0) {
throw caughtExceptions.get(0);
}
但是,在这些情况下,我通常会在process方法中处理异常,或者使用for-loops以旧式方式处理异常.