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118 lines (101 loc) · 3.06 KB
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import java.lang.reflect.*;
public class TestReflect {
public static void main(String[] args) throws Exception {
//m1();
//m2();
//m3("java.lang.Thread");
//m4();
//m5();
//m6();
//String s = "java.lang.String"; //从文件里读出来的
//new s()
//m7();
//m8();
//m9();
m10();
}
private static void m1() {
String s = new String();
Class c = s.getClass();
System.out.println(c);
Class su = c.getSuperclass();
System.out.println(su);
System.out.println(su.getSuperclass());
}
private static void m2() {
Class c = String.class;
System.out.println(c);
}
private static void m3(String className) {
try {
Class.forName(className);
} catch (ClassNotFoundException e) {
System.out.println("this class doesn't exist!");
}
}
private static void m4() {
int m = String.class.getModifiers();
System.out.println(Modifier.isPublic(m));
System.out.println(Modifier.isFinal(m));
System.out.println(Modifier.isStatic(m));
}
private static void m5() {
for(Class c : String.class.getInterfaces()) {
System.out.println(c);
}
System.out.println(java.lang.Comparable.class.isInterface());
}
private static void m6() {
Field[] fs = System.class.getFields();
for(Field f : fs) {
System.out.println(f);
}
}
private static void m7() throws Exception {
Constructor[] cs = String.class.getConstructors();
for(Constructor c : cs) {
System.out.println(c);
for(Class paraClass : c.getParameterTypes()) {
System.out.print(paraClass + " ");
}
System.out.println();
}
String.class.newInstance();
}
private static void m8() throws Exception {
Class[] argClasses = new Class[] {int.class, int.class};
Object[] args = new Object[] {new Integer(12), new Integer(24)};
Constructor c = java.awt.Point.class.getConstructor(argClasses);
Object o = c.newInstance(args);
System.out.println(o);
}
private static void m9() throws Exception {
Class[] argClasses = new Class[] {String.class};
Object[] args = new Object[] {new String("world!")};
Method m = java.lang.String.class.getMethod("concat", argClasses);
String result = (String)m.invoke(new String("hello"), args);
System.out.println(result);
}
private static void m10() throws Exception {
/*
Class cls = Class.forName("java.lang.String");
Object arr = Array.newInstance(cls, 10);
Array.set(arr, 5, "this is a test");
String s = (String)Array.get(arr, 5);
System.out.println(s);
*/
//例中创建了一个 5 x 10 x 15 的整型数组，并为处于 [3][5][10] 的元素赋了值为 37。
//注意，多维数组实际上就是数组的数组，例如，第一个 Array.get 之后，
//arrobj 是一个 10 x 15 的数组。进而取得其中的一个元素，即长度为 15 的数组，
//并使用 Array.setInt 为它的第 10 个元素赋值。
int dims[] = new int[]{5, 10, 15};
Object arr = Array.newInstance(Integer.TYPE, dims);
Object arrobj = Array.get(arr, 3);
Class cls = arrobj.getClass().getComponentType();
System.out.println(cls);
arrobj = Array.get(arrobj, 5);
Array.setInt(arrobj, 10, 37);
int arrcast[][][] = (int[][][]) arr;
System.out.println(arrcast[3][5][10]);
}
}