java.lang.NoSuchMethodException#java.lang.IllegalAccessException源码实例Demo

/**
 * Runs the test using the specified harness.
 *
 * @param harness  the test harness (<code>null</code> not permitted).
 */
public void test(TestHarness harness)
{
    IllegalAccessException object1 = new IllegalAccessException();
    harness.check(object1 != null);
    harness.check(object1.toString(), "java.lang.IllegalAccessException");

    IllegalAccessException object2 = new IllegalAccessException("nothing happens");
    harness.check(object2 != null);
    harness.check(object2.toString(), "java.lang.IllegalAccessException: nothing happens");

    IllegalAccessException object3 = new IllegalAccessException(null);
    harness.check(object3 != null);
    harness.check(object3.toString(), "java.lang.IllegalAccessException");

}
 

/**
  * Get the Thread Context Loader which is a JDK 1.2 feature. If we
  * are running under JDK 1.1 or anything else goes wrong the method
  * returns <code>null<code>.
  *
  *  */
private static ClassLoader getTCL() throws IllegalAccessException, 
  InvocationTargetException {

  // Are we running on a JDK 1.2 or later system?
  Method method = null;
  try {
    method = Thread.class.getMethod("getContextClassLoader", null);
  } catch (NoSuchMethodException e) {
    // We are running on JDK 1.1
    return null;
  }
  
  return (ClassLoader) method.invoke(Thread.currentThread(), null);
}
 

@SuppressWarnings("unchecked")
public static Object invokePrivateMethod(Object target, String methodName, Object... parameters)
    throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
    Method method = getDeclaredMethodIgnoreCase(target.getClass(), methodName, parameters);
    method.setAccessible(true);

    if (parameters != null && parameters.length > 0) {
        return method.invoke(target, (Object[]) parameters);
    }
    return method.invoke(target);
}
 

/**
 * Runs the test using the specified harness.
 *
 * @param harness  the test harness (<code>null</code> not permitted).
 */
public void test(TestHarness harness)
{
    // flag that is set when exception is caught
    boolean caught = false;
    try {
        throw new IllegalAccessException("IllegalAccessException");
    }
    catch (IllegalAccessException e) {
        // correct exception was caught
        caught = true;
    }
    harness.check(caught);
}
 

/**
 * Given a TEnum class and integer value, this method will return
 * the associated constant from the given TEnum class.
 * This method MUST be modified should the name of the 'findByValue' method
 * change.
 *
 * @param enumClass TEnum from which to return a matching constant.
 * @param value Value for which to return the constant.
 *
 * @return The constant in 'enumClass' whose value is 'value' or null if
 *         something went wrong.
 */
public static TEnum getByValue(Class<? extends TEnum> enumClass, int value) {
  try {
    Method method = enumClass.getMethod("findByValue", int.class);
    return (TEnum) method.invoke(null, value);
  } catch (NoSuchMethodException nsme) {
    return null;
  } catch (IllegalAccessException iae) {
    return null;
  } catch (InvocationTargetException ite) {
    return null;
  }
}
 

/**
 * Given a TEnum class and integer value, this method will return
 * the associated constant from the given TEnum class.
 * This method MUST be modified should the name of the 'findByValue' method
 * change.
 *
 * @param enumClass TEnum from which to return a matching constant.
 * @param value Value for which to return the constant.
 *
 * @return The constant in 'enumClass' whose value is 'value' or null if
 *         something went wrong.
 */
public static TEnum getByValue(Class<? extends TEnum> enumClass, int value) {
  try {
    Method method = enumClass.getMethod("findByValue", int.class);
    return (TEnum) method.invoke(null, value);
  } catch (NoSuchMethodException nsme) {
    return null;
  } catch (IllegalAccessException iae) {
    return null;
  } catch (InvocationTargetException ite) {
    return null;
  }
}
 

private static Method getDeclaredMethodIgnoreCase(Class clazz, String methodName, Object... parameters)
    throws NoSuchMethodException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
    if (clazz == null) {
        throw new NoSuchMethodException("Unable to find [" + methodName + "] in this class or any super classes");
    }

    for (Method method : clazz.getDeclaredMethods()) {
        // name match
        if (!method.getName().equalsIgnoreCase(methodName)) {
            continue;
        }

        // length match - null == 0
        Class[] types = method.getParameterTypes();
        boolean parametersIsEmpty = parameters == null || parameters.length == 0;
        boolean typesIsEmpty = types == null || types.length == 0;

        if ((parametersIsEmpty != typesIsEmpty) || (parameters.length != types.length)) {
            continue;
        }

        // isInstance match
        if (!typesIsEmpty) {
            boolean incompatibleTypeFound = false;
            for (int i = 0; i < types.length; i++) {
                if (!types[i].isInstance(parameters[i]) && parameters[i] != null){
                    incompatibleTypeFound = true;
                    break;
                }
            }

            if (incompatibleTypeFound) {
                continue;
            }
        }

        return method;
    }

    return getDeclaredMethodIgnoreCase(clazz.getSuperclass(), methodName, parameters);
}
 

/**
 * Allows us to query any member field of an object (including a private one). This is useful for inspecting and
 * verifying the private member variables of an object in a test. Note that if you change a variable name, you'll
 * no longer get a compile failure for name mismatching, it'll only happen at runtime. This is why this method is
 * only used in tests (We don't do this style of reflection in the app itself). Example usage might be:
 *
 * class Dummy {
 *     private Context context;
 * }
 *
 * Dummy dummy = new Dummy();
 *
 * Context context = TestUtils.getPrivateField(dummy, "context");
 *
 * Return type is based on expected type. If expected type is ambiguous (say for a method that has multiple
 * implementations with various types), you can specify the exact return type with:
 *
 * someFunction(TestUtils.<Context>getPrivateField(dummy, "context");
 *
 * The fieldName is caseInsensitive. If more than one member variable has the same case-insensitive name, the results
 * are indeterminate. This method will check SuperClasses as well. Ordering always returns the value of the variable
 * closest to the current class. For instance, if the class of the object passed in has the field, that one will be
 * retrieved even if the SuperClass also has a field with the same name. If the SuperClass has the field and the
 * current class does not, the SuperClasses will be used, even if it's superClass also has the field declared.
 * Also, never use the same variable name with different cases. Seriously.
 *
 * @param target object to get a field of
 * @param fieldName case insensitive name of the field to retrieve the value of
 * @param <T> type of the field.
 * @return the value of the field named by fieldName in the passed in target object.
 * @throws NoSuchFieldException if the field named does not exist.
 * @throws IllegalAccessException in case it's impossible to access the field due to a permission error. Normally
 * shouldn't happen.
 */
@SuppressWarnings("unchecked")
public static <T> T getPrivateField(Object target, String fieldName)
    throws NoSuchFieldException, IllegalAccessException
{
    Field field = getDeclaredFieldIgnoreCase(target.getClass(), fieldName);
    field.setAccessible(true);
    return (T) field.get(target);
}
 

/**
 * Allows us to set the value of a member variable of an object (even a private one) using reflection. This method
 * is ok to use in test cases but this type of reflection should never be used in the main app.  Note that if you
 * change a variable name, you'll no longer get a compile failure for name mismatching, it'll only happen at runtime.
 * Example of usage might be:
 *
 * class Dummy {
 *     private Context context;
 * }
 *
 * Dummy dummy = new Dummy();
 * Context context = new Context();
 *
 * TestUtils.setPrivateField(dummy, "context", context);
 *
 * The set fieldName is case insensitive. This method will indeterminately set the value to the first fieldName
 * that matches (ordering isn't guaranteed). If a field is not found in the current class, the superClass will also
 * be checked recursively until all SuperClasses are checked for the field. This will be a problem if you have 2 or
 * more member variables with the same name of different cases, which you really shouldn't be doing. Seriously.
 *
 * @param target object to set the value of a member variable
 * @param fieldName is the name of the member variable you will be setting
 * @param fieldValue is the value of that member variable that you want set
 * @throws NoSuchFieldException if the fieldName is not a memberVariable of the given target object
 * @throws IllegalAccessException in case it's impossible to access the field due to a permission error. Normally
 * shouldn't happen.
 */
public static void setPrivateField(Object target, String fieldName, Object fieldValue)
    throws NoSuchFieldException, IllegalAccessException
{
    Field field = getDeclaredFieldIgnoreCase(target.getClass(), fieldName);
    field.setAccessible(true);
    field.set(target, fieldValue);
}