JAVA基础之Optional小窍门

Optional.ofNullable()可以传入空值，并返回Optional，下面咱们看下这个小窍门挺有意思的

public class FilesTest {
    private String testName;
    private String testAge;
    public Optional<String> getTestName() {
        return Optional.ofNullable(testName);
    }
    public void setTestName(String testName) {
        this.testName = testName;
    }
    public String getTestAge() {
        return testAge;
    }
    public void setTestAge(String testAge) {
        this.testAge = testAge;
    }
    public static void main(String[] args) throws Exception{
        FilesTest test = new FilesTest();
        test.setTestAge("12");
        test.setTestName("123");
        String nameResult = test.getTestName().map(testName -> "- " + testName)
                .orElse("No testName");
        System.out.println(nameResult);
        test.setTestName(null);
        nameResult = test.getTestName().map(testName -> "- " + testName)
                .orElse("No testName");
        System.out.println(nameResult);
    }
}
//输出
- 123
No testName

通过一个orElse就可以使null值输出了一个No testName，是不是挺有意思。