java - 有没有办法通过反射识别 Java 16 记录的规范构造函数？

Question

假设我有这样的记录(或任何其他记录):

record X(int i, int j) {
    X(int i) {
        this(i, 0);
    }
    X() {
        this(0, 0);
    }
    X(String i, String j) {
        this(Integer.parseInt(i), Integer.parseInt(j));
    }
}

有没有办法找到这条记录的 canonical constructor通过反射，即在 RecordHeader 中隐式声明的反射?

Answer 1

尝试这个

static <T extends Record> Constructor<T> canonicalConstructorOfRecord(Class<T> recordClass)
        throws NoSuchMethodException, SecurityException {
    Class<?>[] componentTypes = Arrays.stream(recordClass.getRecordComponents())
        .map(rc -> rc.getType())
        .toArray(Class<?>[]::new);
    return recordClass.getDeclaredConstructor(componentTypes);
}

和

Constructor<X> c = canonicalConstructorOfRecord(X.class);
X x = c.newInstance(1, 2);
System.out.println(x);

输出

X[i=1, j=2]