1.获取当前类定义的所有方法，不包括父类和接口的

XXX.class.getDeclaredMethods()

会返回当前类定义的所有方法（包括私有的、静态的、抽象的），但不会返回接口和父类中定义的方法。

2.获取当前类所有的public方法，包括父类和接口的

XXX.class.getMethods()

会返回当前类所有的public方法，包括接口和父类中定义的public方法。

3.获取当前类中所有的方法，包括父类和接口的

private Method[] getClassMethods(Class<?> cls) {
    Map<String, Method> uniqueMethods = new HashMap<String, Method>();
    Class<?> currentClass = cls;
    while (currentClass != null && currentClass != Object.class) {
      addUniqueMethods(uniqueMethods, currentClass.getDeclaredMethods());

      //获取接口中的所有方法
      Class<?>[] interfaces = currentClass.getInterfaces();
      for (Class<?> anInterface : interfaces) {
        addUniqueMethods(uniqueMethods, anInterface.getMethods());
      }
      //获取父类，继续while循环
      currentClass = currentClass.getSuperclass();
    }

    Collection<Method> methods = uniqueMethods.values();

    return methods.toArray(new Method[methods.size()]);
  }

  private void addUniqueMethods(Map<String, Method> uniqueMethods, Method[] methods) {
    for (Method currentMethod : methods) {
      if (!currentMethod.isBridge()) {
      //获取方法的签名，格式是：返回值类型#方法名称:参数类型列表
        String signature = getSignature(currentMethod);
        //检查是否在子类中已经添加过该方法，如果在子类中已经添加过，则表示子类覆盖了该方法，无须再向uniqueMethods集合中添加该方法了
        if (!uniqueMethods.containsKey(signature)) {
          if (canControlMemberAccessible()) {
            try {
              currentMethod.setAccessible(true);
            } catch (Exception e) {
              // Ignored. This is only a final precaution, nothing we can do.
            }
          }
          uniqueMethods.put(signature, currentMethod);
        }
      }
    }
  }

  private String getSignature(Method method) {
    StringBuilder sb = new StringBuilder();
    Class<?> returnType = method.getReturnType();
    if (returnType != null) {
      sb.append(returnType.getName()).append('#');
    }
    sb.append(method.getName());
    Class<?>[] parameters = method.getParameterTypes();
    for (int i = 0; i < parameters.length; i++) {
      if (i == 0) {
        sb.append(':');
      } else {
        sb.append(',');
      }
      sb.append(parameters[i].getName());
    }
    return sb.toString();
  }

  /**
   * Checks whether can control member accessible.
   *
   * @return If can control member accessible, it return {@literal true}
   * @since 3.5.0
   */
  public static boolean canControlMemberAccessible() {
    try {
      SecurityManager securityManager = System.getSecurityManager();
      if (null != securityManager) {
        securityManager.checkPermission(new ReflectPermission("suppressAccessChecks"));
      }
    } catch (SecurityException e) {
      return false;
    }
    return true;
  }

原文:https://blog.csdn.net/u011983531/article/details/80248945