1.属性
/**
* 获取当前运行时类的属性结构
*
* @author shkstart
* @create 2019 下午 3:23
*/
public class FieldTest {
@Test
public void test1(){
Class clazz = Person.class;
//获取属性结构
//getFields():获取当前运行时类及其父类中声明为public访问权限的属性
Field[] fields = clazz.getFields();
for(Field f : fields){
System.out.println(f);
}
System.out.println();
//getDeclaredFields():获取当前运行时类中声明的所有属性。(不包含父类中声明的属性)
Field[] declaredFields = clazz.getDeclaredFields();
for(Field f : declaredFields){
System.out.println(f);
}
}
//权限修饰符 数据类型 变量名
@Test
public void test2(){
Class clazz = Person.class;
Field[] declaredFields = clazz.getDeclaredFields();
for(Field f : declaredFields){
//1.权限修饰符
int modifier = f.getModifiers();
System.out.print(Modifier.toString(modifier) + "\t");
//2.数据类型
Class type = f.getType();
System.out.print(type.getName() + "\t");
//3.变量名
String fName = f.getName();
System.out.print(fName);
System.out.println();
}
}
}
2.方法
/**
* 获取运行时类的方法结构
*
* @author shkstart
* @create 2019 下午 3:37
*/
public class MethodTest {
@Test
public void test1(){
Class clazz = Person.class;
//getMethods():获取当前运行时类及其所有父类中声明为public权限的方法
Method[] methods = clazz.getMethods();
for(Method m : methods){
System.out.println(m);
}
System.out.println();
//getDeclaredMethods():获取当前运行时类中声明的所有方法。(不包含父类中声明的方法)
Method[] declaredMethods = clazz.getDeclaredMethods();
for(Method m : declaredMethods){
System.out.println(m);
}
}
/*
@Xxxx
权限修饰符 返回值类型 方法名(参数类型1 形参名1,...) throws XxxException{}
*/
@Test
public void test2(){
Class clazz = Person.class;
Method[] declaredMethods = clazz.getDeclaredMethods();
for(Method m : declaredMethods){
//1.获取方法声明的注解
Annotation[] annos = m.getAnnotations();
for(Annotation a : annos){
System.out.println(a);
}
//2.权限修饰符
System.out.print(Modifier.toString(m.getModifiers()) + "\t");
//3.返回值类型
System.out.print(m.getReturnType().getName() + "\t");
//4.方法名
System.out.print(m.getName());
System.out.print("(");
//5.形参列表
Class[] parameterTypes = m.getParameterTypes();
if(!(parameterTypes == null && parameterTypes.length == 0)){
for(int i = 0;i < parameterTypes.length;i++){
if(i == parameterTypes.length - 1){
System.out.print(parameterTypes[i].getName() + " args_" + i);
break;
}
System.out.print(parameterTypes[i].getName() + " args_" + i + ",");
}
}
System.out.print(")");
//6.抛出的异常
Class[] exceptionTypes = m.getExceptionTypes();
if(exceptionTypes.length > 0){
System.out.print("throws ");
for(int i = 0;i < exceptionTypes.length;i++){
if(i == exceptionTypes.length - 1){
System.out.print(exceptionTypes[i].getName());
break;
}
System.out.print(exceptionTypes[i].getName() + ",");
}
}
System.out.println();
}
}
}
3.构造器
import com.atguigu.java1.Person;
import org.junit.Test;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
/**
* @author shkstart
* @create 2019 下午 4:19
*/
public class OtherTest {
/*
获取构造器结构
*/
@Test
public void test1(){
Class clazz = Person.class;
//getConstructors():获取当前运行时类中声明为public的构造器
Constructor[] constructors = clazz.getConstructors();
for(Constructor c : constructors){
System.out.println(c);
}
System.out.println();
//getDeclaredConstructors():获取当前运行时类中声明的所有的构造器
Constructor[] declaredConstructors = clazz.getDeclaredConstructors();
for(Constructor c : declaredConstructors){
System.out.println(c);
}
}
/*
获取运行时类的父类
*/
@Test
public void test2(){
Class clazz = Person.class;
Class superclass = clazz.getSuperclass();
System.out.println(superclass);
}
/*
获取运行时类的带泛型的父类
*/
@Test
public void test3(){
Class clazz = Person.class;
Type genericSuperclass = clazz.getGenericSuperclass();
System.out.println(genericSuperclass);
}
/*
获取运行时类的带泛型的父类的泛型
代码:逻辑性代码 vs 功能性代码
*/
@Test
public void test4(){
Class clazz = Person.class;
Type genericSuperclass = clazz.getGenericSuperclass();
ParameterizedType paramType = (ParameterizedType) genericSuperclass;
//获取泛型类型
Type[] actualTypeArguments = paramType.getActualTypeArguments();
// System.out.println(actualTypeArguments[0].getTypeName());
System.out.println(((Class)actualTypeArguments[0]).getName());
}
/*
获取运行时类实现的接口
*/
@Test
public void test5(){
Class clazz = Person.class;
Class[] interfaces = clazz.getInterfaces();
for(Class c : interfaces){
System.out.println(c);
}
System.out.println();
//获取运行时类的父类实现的接口
Class[] interfaces1 = clazz.getSuperclass().getInterfaces();
for(Class c : interfaces1){
System.out.println(c);
}
}
/*
获取运行时类所在的包
*/
@Test
public void test6(){
Class clazz = Person.class;
Package pack = clazz.getPackage();
System.out.println(pack);
}
/*
获取运行时类声明的注解
*/
@Test
public void test7(){
Class clazz = Person.class;
Annotation[] annotations = clazz.getAnnotations();
for(Annotation annos : annotations){
System.out.println(annos);
}
}
}
4.调用运行时类中的指定属性(掌握)
如何操作运行时类中的指定的属性 -- 需要掌握
*/
@Test
public void testField1() throws Exception {
Class clazz = Person.class;
//创建运行时类的对象
Person p = (Person) clazz.newInstance();
//1. getDeclaredField(String fieldName):获取运行时类中指定变量名的属性
Field name = clazz.getDeclaredField("name");
//2.保证当前属性是可访问的
name.setAccessible(true);
//3.获取、设置指定对象的此属性值
name.set(p,"Tom");
System.out.println(name.get(p));
}
5.调用运行时类中的指定属性(掌握)
/**
* 获取运行时类的方法结构
*
* @author shkstart
* @create 2019 下午 3:37
*/
public class MethodTest {
@Test
public void test1(){
Class clazz = Person.class;
//getMethods():获取当前运行时类及其所有父类中声明为public权限的方法
Method[] methods = clazz.getMethods();
for(Method m : methods){
System.out.println(m);
}
System.out.println();
//getDeclaredMethods():获取当前运行时类中声明的所有方法。(不包含父类中声明的方法)
Method[] declaredMethods = clazz.getDeclaredMethods();
for(Method m : declaredMethods){
System.out.println(m);
}
}
/*
@Xxxx
权限修饰符 返回值类型 方法名(参数类型1 形参名1,...) throws XxxException{}
*/
@Test
public void test2(){
Class clazz = Person.class;
Method[] declaredMethods = clazz.getDeclaredMethods();
for(Method m : declaredMethods){
//1.获取方法声明的注解
Annotation[] annos = m.getAnnotations();
for(Annotation a : annos){
System.out.println(a);
}
//2.权限修饰符
System.out.print(Modifier.toString(m.getModifiers()) + "\t");
//3.返回值类型
System.out.print(m.getReturnType().getName() + "\t");
//4.方法名
System.out.print(m.getName());
System.out.print("(");
//5.形参列表
Class[] parameterTypes = m.getParameterTypes();
if(!(parameterTypes == null && parameterTypes.length == 0)){
for(int i = 0;i < parameterTypes.length;i++){
if(i == parameterTypes.length - 1){
System.out.print(parameterTypes[i].getName() + " args_" + i);
break;
}
System.out.print(parameterTypes[i].getName() + " args_" + i + ",");
}
}
System.out.print(")");
//6.抛出的异常
Class[] exceptionTypes = m.getExceptionTypes();
if(exceptionTypes.length > 0){
System.out.print("throws ");
for(int i = 0;i < exceptionTypes.length;i++){
if(i == exceptionTypes.length - 1){
System.out.print(exceptionTypes[i].getName());
break;
}
System.out.print(exceptionTypes[i].getName() + ",");
}
}
System.out.println();
}
}
}