Optional.ofNullable()可以传入空值并返回Optional。让我们来看看这个有趣的技巧：publicclassFilesTest{privateStringtestName;私有字符串测试年龄；publicOptionalgetTestName(){returnOptional.ofNullable(testName);}publicvoidsetTestName(StringtestName){this.testName=testName;}publicStringgetTestAge(){返回测试年龄；}publicvoidsetTestAge(StringtestAge){this.testAge=testAge;}publicstaticvoidmain(String[]args)throwsException{FilesTesttest=newFilesTest();test.setTestAge("12");test.setTestName("123");StringnameResult=test.getTestName().map(testName->"-"+testName).orElse("NotestName");System.out.println(nameResult);测试.setTestName(null);nameResult=test.getTestName().map(testName->"-"+testName).orElse("NotestName");System.out.println(nameRes终极）；}}//Output-123NotestName通过orElse，可以将null值输出为NotestName，是不是很有趣？
