Question

假设我在函数中有几行代码。每一行都有可能抛出Null Pointer Exception。我想让我的函数继续执行行，即使抛出异常！但每次发生异常时，我的函数都会立即返回调用函数而不执行下面的行。我在函数中try-catch异常。以下是我的代码：

        // get duration
        c.set(17, format(search(doc.select("div.course-info"), "h3", "Duration").select("p").first().ownText()));

        // get start date
        c.set(46, format(doc.select("div.course-info.l-span-7").first().select("p").first().ownText()));

        // get study mode
        c.set(18, format(combine(search(doc.select("div.course-info.l-span-4"), "h3", "Study").select("li"))));

        // get career
        c.set(52, format(doc.select("div#cs-aims-objectives").first().select("div").first().html()));

        // get professional accredition
        c.set(38, format(search(doc.select("div.section-highlight"), "h3", "Professional").select("div").first().html()));

        // get scholarships
        c.set(24, format(search(doc.select("div.media-body"), "h4", "Scholarships").select("div").html()));

即使发生异常，我想让我的函数继续执行，比如第6行。我将如何解决这个问题？我可以在每一行之前设置一个条件，检查它是否为空，但这需要花费太多时间 - 我有300行代码......

Answer 1

我使用enum来表示这样的模式。

enum Thing {

    Duration {

                @Override
                void set(Something c, Doc doc) {
                    c.set(17, format(search(doc.select("div.course-info"), "h3", "Duration").select("p").first().ownText()));
                }
            },
    StartDate {

                @Override
                void set(Something c, Doc doc) {
                    c.set(46, format(doc.select("div.course-info.l-span-7").first().select("p").first().ownText()));
                }
            },
    StudyMode {

                @Override
                void set(Something c, Doc doc) {
                    c.set(18, format(combine(search(doc.select("div.course-info.l-span-4"), "h3", "Study").select("li"))));
                }
            },
    Career {

                @Override
                void set(Something c, Doc doc) {
                    c.set(52, format(doc.select("div#cs-aims-objectives").first().select("div").first().html()));
                }
            },
    ProfessionalAccreditation {

                @Override
                void set(Something c, Doc doc) {
                    c.set(38, format(search(doc.select("div.section-highlight"), "h3", "Professional").select("div").first().html()));
                }
            },
    Scholarships {

                @Override
                void set(Something c, Doc doc) {
                    c.set(24, format(search(doc.select("div.media-body"), "h4", "Scholarships").select("div").html()));
                }
            };

    abstract void set(Something c, Doc doc);
}

public void test() {
    for (Thing t : Thing.values()) {
        try {
            t.set(c, doc);
        } catch (Exception e) {
            // Log the failure and carry on.
        }
    }
}

Answer 2

这样做。一些周到的全局查找和替换以及一些键盘弯头（手指？）润滑脂将使所有300行转换为此形式的速度比您想象的要快得多。

  public static void main(String args[]) {
    CObject c = new CObject(); // Whatever 'c' is, obtained however it needs to be
    Document doc = new Document(); // Obtained however 'doc' needs to be
    setStuff(c, doc, 0);
  }

public void setStuff(CObject c, Document doc, int location) {

int locn = location;
try {
  switch(locn) {
    case 0:
            locn++;
            c.set(17, format(search(doc.select("div.course-info"), "h3", "Duration").select("p").first().ownText()));
    case 1:
            locn++;
            c.set(46, format(doc.select("div.course-info.l-span-7").first().select("p").first().ownText()));
    case 2:
            locn++;
            c.set(18, format(combine(search(doc.select("div.course-info.l-span-4"), "h3", "Study").select("li"))));
    case 3:
            locn++;
            c.set(52, format(doc.select("div#cs-aims-objectives").first().select("div").first().html()));
    case 4:
            locn++;
            c.set(38, format(search(doc.select("div.section-highlight"), "h3", "Professional").select("div").first().html()));
    case 5:
            locn++;
            c.set(24, format(search(doc.select("div.media-body"), "h4", "Scholarships").select("div").html()));
    default:
            return;
   }
  } catch (Exception e) {
    // do whatever with e
    setStuff(c, doc, locn);
  }
 }

即使抛出异常，如何保持函数运行？

2 个答案: