\u53cd\u5c04\uff08Reflection\uff09<\/strong> \u662f\u4e00\u79cd\u5728\u8fd0\u884c\u65f6\uff08Runtime\uff09<\/strong> \u52a8\u6001\u5206\u6790\u3001\u68c0\u67e5\u548c\u64cd\u4f5c\u7c7b\u3001\u65b9\u6cd5\u3001\u5b57\u6bb5\u3001\u6784\u9020\u65b9\u6cd5\u7b49\u7a0b\u5e8f\u7ed3\u6784\u7684\u80fd\u529b\u3002<\/p>\n\n\n\n \u901a\u4fd7\u6765\u8bf4\uff0c\u901a\u8fc7Java\u4e2d\u7684\u53cd\u5c04\u673a\u5236\uff0c\u53ef\u4ee5\u7a0b\u5e8f\u8fd0\u884c\u671f\u95f4\uff0c\u5728\u4e0d\u77e5\u9053\u5177\u4f53\u7c7b\u6216\u8005\u5bf9\u8c61\u7684\u60c5\u51b5\u4e0b\uff0c\u901a\u8fc7\u8be5\u7c7b\u7684\u5b57\u8282\u7801\u5bf9\u8c61\uff0c\u52a8\u6001\u52a0\u8f7d\u7c7b\u3001\u521b\u5efa\u5bf9\u8c61\u3001\u8c03\u7528\u65b9\u6cd5\u3001\u8bbf\u95ee\u5b57\u6bb5\uff0c\u751a\u81f3\u662f\u4fee\u6539\u79c1\u6709\u6210\u5458\u3002<\/p>\n\n\n\n \u53cd\u5c04\u63d0\u4f9b\u4e86\u4e00\u79cd\u5168\u65b0\u7684\u521b\u5efa\u5bf9\u8c61\uff0c\u8c03\u7528\u65b9\u6cd5\uff0c\u8bbf\u95ee\u6210\u5458\u53d8\u91cf\u7684\u5f62\u5f0f\u3002<\/p>\n\n\n\n \u53cd\u5c04\u7684\u8d77\u70b9\u662f\u5b57\u8282\u7801\u5bf9\u8c61\u3002<\/p>\n\n\n\n \u6ce8\u610f:<\/strong><\/p>\n\n\n\n \u65e0\u8bba\u901a\u8fc7\u4ec0\u4e48\u65b9\u5f0f\u83b7\u53d6\u7684\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61 \u90fd\u662f\u540c\u4e00\u4e2a<\/p>\n\n\n\n Demo<\/p>\n\n\n\n \u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6240\u6709\u6784\u9020\u65b9\u6cd5<\/strong><\/p>\n\n\n\n \u83b7\u53d6\u6307\u5b9a\u6784\u9020\u65b9\u6cd5<\/strong><\/p>\n\n\n\n \u4f7f\u7528Constructor\u521b\u5efa\u5bf9\u8c61<\/p>\n\n\n\n \u66b4\u529b\u7834\u89e3<\/p>\n\n\n\n \u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6240\u6709\u6210\u5458\u53d8\u91cf<\/strong><\/p>\n\n\n\n \u83b7\u53d6\u6307\u5b9a\u6210\u5458\u53d8\u91cf<\/strong><\/p>\n\n\n\n \u901a\u8fc7Field\u8bfb\u5199\u5bf9\u8c61\u7684\u6210\u5458\u53d8\u91cf(\u53ef\u66b4\u529b\u7834\u89e3)<\/strong><\/p>\n\n\n\n \u83b7\u53d6\u6240\u6709\u6210\u5458\u65b9\u6cd5<\/strong><\/p>\n\n\n\n \u83b7\u53d6\u6307\u5b9a\u7684\u6210\u5458\u65b9\u6cd5<\/strong><\/p>\n\n\n\n \u5229\u7528Method\u8c03\u7528\u5bf9\u8c61\u7684\u65b9\u6cd5<\/strong><\/p>\n\n\n\n \u5176\u4ed6API<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" \u4ec0\u4e48\u662f\u53cd\u5c04 \u53cd\u5c04\uff08Reflection\uff09 \u662f\u4e00\u79cd\u5728\u8fd0\u884c\u65f6\uff08Runtime\uff09 \u52a8\u6001\u5206\u6790\u3001\u68c0\u67e5\u548c\u64cd\u4f5c\u7c7b\u3001\u65b9\u6cd5\u3001\u5b57\u6bb5 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[12],"class_list":["post-163","post","type-post","status-publish","format-standard","hentry","category-learn","tag-java"],"_links":{"self":[{"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/posts\/163","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/comments?post=163"}],"version-history":[{"count":2,"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/posts\/163\/revisions"}],"predecessor-version":[{"id":184,"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/posts\/163\/revisions\/184"}],"wp:attachment":[{"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/media?parent=163"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/categories?post=163"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/larkdrop.cafe\/index.php\/wp-json\/wp\/v2\/tags?post=163"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\u83b7\u53d6\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61\u7684\u51e0\u79cd\u65b9\u5f0f<\/h2>\n\n\n\n
\n
package _23reflect.com.cskaoyan._02cls;
\u200b
\/*
\u83b7\u53d6\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61\u7684\u51e0\u79cd\u65b9\u5f0f
*\/
public class Demo {
public static void main(String[] args) throws ClassNotFoundException {
\/\/ \u5bf9\u8c61.getClass
A a = new A();
Class<? extends A> c1 = a.getClass();
\u200b
\/\/ \u7c7b\u540d.class
Class<A> c2 = A.class;
\u200b
System.out.println(c1 == c2);
\u200b
\/\/ Class.forName(\u5168\u9650\u5b9a\u540d)
Class<?> c3 = Class.forName(\"_23reflect.com.cskaoyan._02cls.A\");
\u200b
System.out.println(c1 == c3);
\u200b
\/\/ ClassLoader.loadClass(String className)
ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
Class<?> c4 = systemClassLoader.loadClass(\"_23reflect.com.cskaoyan._02cls.A\");
System.out.println(c1 == c4);
\u200b
}
}
\u200b
class A{
\u200b
}<\/pre>\n\n\n\n\u5173\u4e8eClass<\/h2>\n\n\n\n
Class<\/code> \u7c7b\u7684\u5b9e\u4f8b\u8868\u793a\u6b63\u5728\u8fd0\u884c\u7684 Java \u5e94\u7528\u7a0b\u5e8f\u4e2d\u7684\u7c7b\u548c\u63a5\u53e3<\/p>\n\n\n\nClass<\/code> \u6ca1\u6709\u516c\u5171\u6784\u9020\u65b9\u6cd5\u3002Class<\/code> \u5bf9\u8c61\u662f\u5728\u52a0\u8f7d\u7c7b\u65f6\u7531 Java \u865a\u62df\u673a\u4ee5\u53ca\u901a\u8fc7\u8c03\u7528\u7c7b\u52a0\u8f7d\u5668\u4e2d\u7684 defineClass<\/code> \u65b9\u6cd5\u81ea\u52a8\u6784\u9020\u7684\u3002<\/p>\n\n\n\n\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6784\u9020\u65b9\u6cd5(Constructor)<\/h2>\n\n\n\n
\/\/ \u83b7\u53d6\u6240\u6709\u7684public\u4fee\u9970\u7684\u6784\u9020\u65b9\u6cd5
Constructor[] getConstructors()
\/\/ \u83b7\u53d6\u6240\u6709\u7684\u6784\u9020\u65b9\u6cd5\uff0c\u5305\u62ec\u79c1\u6709\u6784\u9020\u65b9\u6cd5
Constructor[] getDeclaredConstructors()<\/pre>\n\n\n\nConstructor<T> getConstructor(Class<?>... parameterTypes)
Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes)<\/pre>\n\n\n\nPerson p = new Person(\"zs\",20,true)
newInstance(\u53c2\u6570\u5217\u8868)<\/pre>\n\n\n\nsetAccessible(true) <\/pre>\n\n\n\n
package _23reflect.com.cskaoyan._04api;
\u200b
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
\u200b
\u200b
\u200b
public class ConstructorTest {
public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
\/\/ \u53cd\u5c04\u6280\u672f\u7684\u8d77\u70b9 \u83b7\u53d6\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61
Class<?> stuCls = Class.forName(\"_23reflect.com.cskaoyan.bean.Person\");
\u200b
System.out.println(\"\u83b7\u53d6\u6240\u6709\u7684public\u7684\u6784\u9020\u65b9\u6cd5----\");
\/\/ Constructor[] getConstructors()
Constructor<?>[] constructors = stuCls.getConstructors();
for (Constructor<?> constructor : constructors) {
System.out.println(constructor);
}
\u200b
System.out.println(\"\u83b7\u53d6\u6240\u6709\u7684\u6784\u9020\u65b9\u6cd5----\");
\u200b
\/\/Constructor[] getDeclaredConstructors()
Constructor<?>[] declaredConstructors = stuCls.getDeclaredConstructors();
for (Constructor<?> constructor : declaredConstructors) {
System.out.println(constructor);
}
System.out.println(\"\u83b7\u53d6\u6307\u5b9a\u7684public\u7684\u6784\u9020\u65b9\u6cd5----\");
\/\/ Constructor<T> getConstructor(Class<?>... parameterTypes)
Constructor<?> constructor = stuCls.getConstructor(String.class, int.class, boolean.class);
\/\/Constructor<?> constructor = stuCls.getConstructor(String.class, int.class);
\/\/ java.lang.NoSuchMethodException
\u200b
\u200b
System.out.println(constructor);
System.out.println(\"\u83b7\u53d6\u6307\u5b9a\u7684\u6784\u9020\u65b9\u6cd5----\");
\/\/Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes)
Constructor<?> declaredConstructor = stuCls.getDeclaredConstructor(String.class, int.class);
System.out.println(declaredConstructor);
\u200b
\/\/ \u4f7f\u7528\u6784\u9020\u65b9\u6cd5\u5bf9\u8c61\u521b\u5efa\u5bf9\u8c61
\/\/ newInstance
Object o = constructor.newInstance(\"zs\", 20, true);
System.out.println(o);
\u200b
\/\/ java.lang.IllegalAccessException
\/\/ setAccessible(true) \u5ffd\u7565java\u8bed\u6cd5\u68c0\u67e5
declaredConstructor.setAccessible(true);
Object o1 = declaredConstructor.newInstance(\"ls\", 21);
System.out.println(o1);
\u200b
\u200b
}
}
\u200b<\/pre>\n\n\n\n\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6210\u5458\u53d8\u91cf(Field)<\/h2>\n\n\n\n
\/\/ \u83b7\u53d6\u6240\u6709public \u4fee\u9970\u7684\u6210\u5458\u53d8\u91cf,\u5305\u62ec\u7ee7\u627f\u81ea\u7236\u7c7b\u4e2d\u7684\u6210\u5458
Field[] getFields()
\/\/ \u83b7\u53d6\u6240\u6709\u5728\u8be5\u7c7b\u4e2d\u5b9a\u4e49\u7684\u6210\u5458\uff0c\u5305\u62ec\u79c1\u6709\u6210\u5458
Field[] getDeclaredFields()<\/pre>\n\n\n\nField getField(String name)
Field getDeclaredField(String name)<\/pre>\n\n\n\nObject get(Object obj)\uff1a\u83b7\u53d6\u503c\uff0c\u4f20\u5165\u5bf9\u8c61
void set(Object obj, Object value)\uff1a\u8d4b\u503c\uff0c\u4f20\u5165\u5bf9\u8c61<\/pre>\n\n\n\npackage _23reflect.com.cskaoyan._04api;
\u200b
import _23reflect.com.cskaoyan.bean.Person;
\u200b
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
\u200b
\/*
\u53cd\u5c04\u83b7\u53d6\u6210\u5458\u53d8\u91cf
\u200b
*\/
public class FieldTest {
public static void main(String[] args) throws Exception{
\/\/ \u83b7\u53d6\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61
Class<?> personCls = Class.forName(\"_23reflect.com.cskaoyan.bean.Person\");
System.out.println(\"\u83b7\u53d6\u6240\u6709\u7684public\u7684\u6210\u5458\u53d8\u91cf------\");
\/\/ Field[] getFields()
Field[] fields = personCls.getFields();
for (Field field : fields) {
System.out.println(field);
}
System.out.println(\"\u83b7\u53d6\u6240\u6709\u7684\u6210\u5458\u53d8\u91cf------\");
\u200b
\/\/Field[] getDeclaredFields()
Field[] declaredFields = personCls.getDeclaredFields();
for (Field field : declaredFields) {
System.out.println(field);
}
System.out.println(\"\u83b7\u53d6\u6307\u5b9a\u7684public\u7684\u6210\u5458\u53d8\u91cf------\");
\/\/ Field getField(String name)
Field nameField = personCls.getField(\"name\");
System.out.println(nameField);
System.out.println(\"\u83b7\u53d6\u6307\u5b9a\u7684\u6210\u5458\u53d8\u91cf------\");
\u200b
\/\/Field getDeclaredField(String name)
Field ageField = personCls.getDeclaredField(\"age\");
System.out.println(ageField);
\u200b
\/\/ \u7ed9\u6210\u5458\u53d8\u91cf\u8d4b\u503c \u83b7\u53d6\u6210\u5458\u53d8\u91cf\u7684\u503c
\/\/void set(Object obj, Object value)\uff1a\u8d4b\u503c\uff0c\u4f20\u5165\u5bf9\u8c61
Constructor<?> declaredConstructor = personCls.getDeclaredConstructor();
\/\/ \u5b9e\u4f8b\u5316\u5bf9\u8c61
Object o = declaredConstructor.newInstance();
nameField.set(o, \"zs\");
System.out.println(o);
\u200b
ageField.setAccessible(true);
ageField.set(o, 22);
System.out.println(o);
\/\/ Object get(Object obj)\uff1a\u83b7\u53d6\u503c\uff0c\u4f20\u5165\u5bf9\u8c61
Object o1 = nameField.get(o);
System.out.println(o1);
}
}
\u200b<\/pre>\n\n\n\n\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u6210\u5458\u65b9\u6cd5(Method)<\/h2>\n\n\n\n
\/\/ \u83b7\u53d6\u6240\u6709\u7684public\u4fee\u9970\u7684\u65b9\u6cd5,\u5305\u62ec\u7ee7\u627f\u7684\u7236\u7c7b\u4e2d\u7684\u65b9\u6cd5
Method[] getMethods();
\u200b
\/\/ \u83b7\u53d6\u6240\u6709\u5728\u8be5\u7c7b\u4e2d\u5b9a\u4e49\u7684\u65b9\u6cd5\uff0c\u5305\u62ec\u79c1\u6709\u65b9\u6cd5\uff0c\u4e0d\u5305\u62ec\u7236\u7c7b\u4e2d\u7684\u65b9\u6cd5
Method[] getDeclaredMethods()<\/pre>\n\n\n\nMethod getMethod(String name, Class<?>... parameterTypes)
Method getDeclaredMethod(String name, Class<?>... parameterTypes)<\/pre>\n\n\n\nObject invoke(Object obj, Object... args)<\/pre>\n\n\n\n
package _23reflect.com.cskaoyan._04api;
\u200b
import _23reflect.com.cskaoyan.bean.Person;
\u200b
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
\u200b
\/**
* @description:
* @author: \u666f\u5929
* @date: 2022\/10\/24 14:39
**\/
\/*
\u901a\u8fc7\u53cd\u5c04\u83b7\u53d6\u65b9\u6cd5
*\/
public class MethodTest {
public static void main(String[] args) throws Exception{
\/\/ \u83b7\u53d6\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61
Class<?> personCls = Class.forName(\"_23reflect.com.cskaoyan.bean.Person\");
\u200b
System.out.println(\"\u83b7\u53d6\u6240\u6709\u7684public\u7684\u65b9\u6cd5----\");
\/\/ Method[] getMethods()
Method[] methods = personCls.getMethods();
for (Method method : methods) {
System.out.println(method);
}
System.out.println(\"\u83b7\u53d6\u6240\u6709\u7684\u65b9\u6cd5----\");
\u200b
\/\/Method[] getDeclaredMethods()
Method[] declaredMethods = personCls.getDeclaredMethods();
for (Method method : declaredMethods) {
System.out.println(method);
}
\u200b
System.out.println(\"\u83b7\u53d6\u6307\u5b9a\u7684public\u7684\u65b9\u6cd5----\");
\/\/ Method getMethod(String name, Class<?>... parameterTypes)
Method eatMethod1 = personCls.getMethod(\"eat\");
System.out.println(eatMethod1);
\u200b
System.out.println(\"\u83b7\u53d6\u6307\u5b9a\u7684\u65b9\u6cd5----\");
\u200b
\/\/Method getDeclaredMethod(String name, Class<?>... parameterTypes)
Method eatMethod2 = personCls.getDeclaredMethod(\"eat\", String.class);
System.out.println(eatMethod2);
\u200b
\/\/Person p = new Person();
\/\/p.eat();
\u200b
\/\/ \u53cd\u5c04\u8c03\u7528\u65b9\u6cd5
\/\/ Object invoke(Object obj, Object... args)
Constructor<?> declaredConstructor = personCls.getDeclaredConstructor();
Object o = declaredConstructor.newInstance();
Object invoke = eatMethod1.invoke(o);
System.out.println(invoke);
\u200b
eatMethod2.setAccessible(true);
eatMethod2.invoke(o, \"apple\");
\u200b
}
}
\u200b<\/pre>\n\n\n\n\u8865\u5145<\/h2>\n\n\n\n
package _23reflect.com.cskaoyan.bean;
\u200b
\/**
* @description:
* @author: \u666f\u5929
* @date: 2022\/10\/24 11:31
**\/
\u200b
public class Person {
\/\/ \u5b9a\u4e49\u6210\u5458\u53d8\u91cf
public String name;
private int age;
boolean gender;
\u200b
\/\/ \u6784\u9020\u65b9\u6cd5
\u200b
public Person(String name, int age, boolean gender) {
this.name = name;
this.age = age;
this.gender = gender;
}
\u200b
private Person(String name, int age) {
this.name = name;
this.age = age;
}
\u200b
public Person() {
}
\u200b
\/\/ \u5b9a\u4e49\u6210\u5458\u65b9\u6cd5
\u200b
@Override
public String toString() {
return \"Person{\" +
\"name='\" + name + '\\'' +
\", age=\" + age +
\", gender=\" + gender +
'}';
}
\u200b
public String eat(){
System.out.println(\"eat food!\");
return \"\u5403\u4e86\";
}
\u200b
private void eat(String food){
System.out.println(\"eat \" + food);
}
}
\u200b
\u200b
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
\u200b
\u200b
public class OtherApi {
public static void main(String[] args) throws Exception{
\/\/ \u83b7\u53d6\u5b57\u8282\u7801\u6587\u4ef6\u5bf9\u8c61
Class<?> c = Class.forName(\"_23reflect.com.cskaoyan.bean.Person\");
\/\/Class<?> c = Class.forName(\"java.io.OutputStream\");
\/\/ \u83b7\u53d6\u5168\u9650\u5b9a\u7c7b\u540d
System.out.println(c.getName());
\/\/ \u83b7\u53d6\u7b80\u5355\u540d\u79f0
System.out.println(\"c.getSimpleName() = \" + c.getSimpleName());
\/\/ \u83b7\u53d6\u7236\u7c7b
Class<?> superclass = c.getSuperclass();
System.out.println(\"superclass = \" + superclass.getSimpleName());
\u200b
\/\/ \u83b7\u53d6\u5b9e\u73b0\u7684\u63a5\u53e3
Class<?>[] interfaces = c.getInterfaces();
for (Class<?> i : interfaces) {
System.out.println(i);
}
\/\/ \u83b7\u53d6\u7c7b\u52a0\u8f7d\u5668
ClassLoader classLoader = c.getClassLoader();
System.out.println(\"classLoader = \" + classLoader);
\u200b
\/\/ \u83b7\u53d6name\u8fd9\u4e2a\u6210\u5458\u53d8\u91cf\u5bf9\u8c61
Field nameField = c.getDeclaredField(\"name\");
\/\/ \u83b7\u53d6\u6743\u9650\u4fee\u9970\u7b26
int modifiers = nameField.getModifiers();
System.out.println(modifiers);
\/\/ static String toString(int mod)
\/\/ \u8fd4\u56de\u63cf\u8ff0\u6307\u5b9a\u4fee\u9970\u7b26\u4e2d\u7684\u8bbf\u95ee\u4fee\u9970\u7b26\u6807\u5fd7\u7684\u5b57\u7b26\u4e32\u3002
String s = Modifier.toString(modifiers);
System.out.println(\"s = \" + s);
\u200b
\/\/ \u83b7\u53d6eat(String s)\u65b9\u6cd5\u5bf9\u8c61
Method eatMethod = c.getDeclaredMethod(\"eat\", String.class);
Class<?> returnType = eatMethod.getReturnType();
System.out.println(\"returnType = \" + returnType);
Class<?>[] parameterTypes = eatMethod.getParameterTypes();
for (Class<?> parameterType : parameterTypes) {
System.out.println(parameterType.getSimpleName());
}
}
}
\u200b
\u200b<\/pre>\n\n\n\n