Introduction to the method of obtaining a class in java-javaTutorial-php.cn

Introduction to the method of obtaining a class in java

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Release： 2017-06-30 10:33:55

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Get all public methods of the class including the public methods of the parent class through the class.getMethos() method.

 1 import lombok.Data; 2  3 /** 4  * Created by hunt on 2017/6/27. 5  
 * 测试的实体类 6  * @Data 编译后会自动生成set、get、无惨构造、equals、canEqual、hashCode、toString方法 7  
 */ 8 @Data 9 public class Person {10     private String name;11     public String nickName;12     private int age;13     private void say(){14         System.out.println("say hunt");15     }16 }

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 1 import java.lang.reflect.Method; 2  3 /** 4  * Created by hunt on 2017/6/27. 5  
 */ 6 public class NewInstanceTest { 7     public static void main(String[] args) { 8         
 Class<Person> personClass = Person.class; 9         try {10             
 Method[] methods = personClass.getMethods();11             for (Method m:methods) {12                 System.out.println(m);13             }14         } catch (Exception e) {15             e.printStackTrace();16         }17     }18 }

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Get all properties of the class (public, protected, default, and private methods) through the class.getDeclaredMethods() method.

 1 import java.lang.reflect.Method; 2  3 /** 4  * Created by hunt on 2017/6/27. 5  
 */ 6 public class NewInstanceTest { 7     public static void main(String[] args) { 8         
 Class<Person> personClass = Person.class; 9         try {10             
 Method[] methods = personClass.getDeclaredMethods();11             for (Method m:methods) {12                 
 System.out.println(m);13             }14         } catch (Exception e) {15             
 e.printStackTrace();16         }17     }18 }

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Note: The elements in the returned method array are not sorted, nor in any particular order.

Get the specific method:

 1 import java.lang.reflect.Method; 2  3 /** 4  * Created by hunt on 2017/6/27. 5  */ 6 public class NewInstanceTest { 7     public static void main(String[] args) { 8         Class<Person> personClass = Person.class; 9         try {10             Person p = personClass.newInstance();11             Method method = personClass.getMethod("setName", String.class);12             method.invoke(p,"hunt");13             System.out.println(p);14             method = personClass.getMethod("getName");15             System.out.println("getName方法"+method.invoke(p));16             method = personClass.getDeclaredMethod("say");17             method.setAccessible(true);//私有方法要授权18             method.invoke(p);19         } catch (Exception e) {20             e.printStackTrace();21         }22     }23 }

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Summary: personClass.getDeclaredMethod("say");

Method.setAccessible(true);

Based on the protection of attributes, the default is false. This is equivalent to an authorization process, setting true to allow the operation of this attribute.

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