org.springframework.core.convert.Property#org.springframework.expression.AccessException源码实例Demo

@Override
public boolean canRead(EvaluationContext context, Object target, String name) throws AccessException {
	if (target == null) {
		return false;
	}

	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());
	if (type.isArray()) {
		return false;
	}

	if (this.member instanceof Method) {
		Method method = (Method) this.member;
		String getterName = "get" + StringUtils.capitalize(name);
		if (getterName.equals(method.getName())) {
			return true;
		}
		getterName = "is" + StringUtils.capitalize(name);
		return getterName.equals(method.getName());
	}
	else {
		Field field = (Field) this.member;
		return field.getName().equals(name);
	}
}
 

private MethodExecutor findAccessorForMethod(String name, List<TypeDescriptor> argumentTypes,
		Object targetObject, EvaluationContext evaluationContext) throws SpelEvaluationException {

	List<MethodResolver> methodResolvers = evaluationContext.getMethodResolvers();
	if (methodResolvers != null) {
		for (MethodResolver methodResolver : methodResolvers) {
			try {
				MethodExecutor methodExecutor = methodResolver.resolve(
						evaluationContext, targetObject, name, argumentTypes);
				if (methodExecutor != null) {
					return methodExecutor;
				}
			}
			catch (AccessException ex) {
				throw new SpelEvaluationException(getStartPosition(), ex,
						SpelMessage.PROBLEM_LOCATING_METHOD, name, targetObject.getClass());
			}
		}
	}

	throw new SpelEvaluationException(getStartPosition(), SpelMessage.METHOD_NOT_FOUND,
			FormatHelper.formatMethodForMessage(name, argumentTypes),
			FormatHelper.formatClassNameForMessage(
					targetObject instanceof Class ? ((Class<?>) targetObject) : targetObject.getClass()));
}
 

private MethodExecutor findAccessorForMethod(String name, List<TypeDescriptor> argumentTypes,
		Object targetObject, EvaluationContext evaluationContext) throws SpelEvaluationException {

	List<MethodResolver> methodResolvers = evaluationContext.getMethodResolvers();
	if (methodResolvers != null) {
		for (MethodResolver methodResolver : methodResolvers) {
			try {
				MethodExecutor methodExecutor = methodResolver.resolve(
						evaluationContext, targetObject, name, argumentTypes);
				if (methodExecutor != null) {
					return methodExecutor;
				}
			}
			catch (AccessException ex) {
				throw new SpelEvaluationException(getStartPosition(), ex,
						SpelMessage.PROBLEM_LOCATING_METHOD, name, targetObject.getClass());
			}
		}
	}

	throw new SpelEvaluationException(getStartPosition(), SpelMessage.METHOD_NOT_FOUND,
			FormatHelper.formatMethodForMessage(name, argumentTypes),
			FormatHelper.formatClassNameForMessage(
					targetObject instanceof Class ? ((Class<?>) targetObject) : targetObject.getClass()));
}
 

@Nullable
private TypeDescriptor getTypeDescriptor(EvaluationContext context, Object target, String name) {
	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());

	if (type.isArray() && name.equals("length")) {
		return TypeDescriptor.valueOf(Integer.TYPE);
	}
	PropertyCacheKey cacheKey = new PropertyCacheKey(type, name, target instanceof Class);
	TypeDescriptor typeDescriptor = this.typeDescriptorCache.get(cacheKey);
	if (typeDescriptor == null) {
		// Attempt to populate the cache entry
		try {
			if (canRead(context, target, name) || canWrite(context, target, name)) {
				typeDescriptor = this.typeDescriptorCache.get(cacheKey);
			}
		}
		catch (AccessException ex) {
			// Continue with null type descriptor
		}
	}
	return typeDescriptor;
}
 

public boolean isWritableProperty(String name, TypedValue contextObject, EvaluationContext evalContext)
		throws EvaluationException {

	List<PropertyAccessor> accessorsToTry =
			getPropertyAccessorsToTry(contextObject.getValue(), evalContext.getPropertyAccessors());
	if (accessorsToTry != null) {
		for (PropertyAccessor accessor : accessorsToTry) {
			try {
				if (accessor.canWrite(evalContext, contextObject.getValue(), name)) {
					return true;
				}
			}
			catch (AccessException ex) {
				// let others try
			}
		}
	}
	return false;
}
 

/**
 * Go through the list of registered constructor resolvers and see if any can find a
 * constructor that takes the specified set of arguments.
 * @param typeName the type trying to be constructed
 * @param argumentTypes the types of the arguments supplied that the constructor must take
 * @param state the current state of the expression
 * @return a reusable ConstructorExecutor that can be invoked to run the constructor or null
 * @throws SpelEvaluationException if there is a problem locating the constructor
 */
private ConstructorExecutor findExecutorForConstructor(String typeName,
		List<TypeDescriptor> argumentTypes, ExpressionState state)
		throws SpelEvaluationException {

	EvaluationContext evalContext = state.getEvaluationContext();
	List<ConstructorResolver> ctorResolvers = evalContext.getConstructorResolvers();
	if (ctorResolvers != null) {
		for (ConstructorResolver ctorResolver : ctorResolvers) {
			try {
				ConstructorExecutor ce = ctorResolver.resolve(state.getEvaluationContext(), typeName, argumentTypes);
				if (ce != null) {
					return ce;
				}
			}
			catch (AccessException ex) {
				throw new SpelEvaluationException(getStartPosition(), ex,
						SpelMessage.CONSTRUCTOR_INVOCATION_PROBLEM, typeName,
						FormatHelper.formatMethodForMessage("", argumentTypes));
			}
		}
	}
	throw new SpelEvaluationException(getStartPosition(), SpelMessage.CONSTRUCTOR_NOT_FOUND, typeName,
			FormatHelper.formatMethodForMessage("", argumentTypes));
}
 

@Override
public TypedValue execute(EvaluationContext context, Object... arguments) throws AccessException {
	try {
		ReflectionHelper.convertArguments(
				context.getTypeConverter(), arguments, this.ctor, this.varargsPosition);
		if (this.ctor.isVarArgs()) {
			arguments = ReflectionHelper.setupArgumentsForVarargsInvocation(
					this.ctor.getParameterTypes(), arguments);
		}
		ReflectionUtils.makeAccessible(this.ctor);
		return new TypedValue(this.ctor.newInstance(arguments));
	}
	catch (Exception ex) {
		throw new AccessException("Problem invoking constructor: " + this.ctor, ex);
	}
}
 

@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
	BeanResolver beanResolver = state.getEvaluationContext().getBeanResolver();
	if (beanResolver == null) {
		throw new SpelEvaluationException(
				getStartPosition(), SpelMessage.NO_BEAN_RESOLVER_REGISTERED, this.beanName);
	}

	try {
		return new TypedValue(beanResolver.resolve(state.getEvaluationContext(), this.beanName));
	}
	catch (AccessException ex) {
		throw new SpelEvaluationException(getStartPosition(), ex, SpelMessage.EXCEPTION_DURING_BEAN_RESOLUTION,
			this.beanName, ex.getMessage());
	}
}
 

@Nullable
private TypeDescriptor getTypeDescriptor(EvaluationContext context, Object target, String name) {
	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());

	if (type.isArray() && name.equals("length")) {
		return TypeDescriptor.valueOf(Integer.TYPE);
	}
	PropertyCacheKey cacheKey = new PropertyCacheKey(type, name, target instanceof Class);
	TypeDescriptor typeDescriptor = this.typeDescriptorCache.get(cacheKey);
	if (typeDescriptor == null) {
		// Attempt to populate the cache entry
		try {
			if (canRead(context, target, name) || canWrite(context, target, name)) {
				typeDescriptor = this.typeDescriptorCache.get(cacheKey);
			}
		}
		catch (AccessException ex) {
			// Continue with null type descriptor
		}
	}
	return typeDescriptor;
}
 

@Override
public TypedValue getValueInternal(ExpressionState state) throws EvaluationException {
	BeanResolver beanResolver = state.getEvaluationContext().getBeanResolver();
	if (beanResolver == null) {
		throw new SpelEvaluationException(
				getStartPosition(), SpelMessage.NO_BEAN_RESOLVER_REGISTERED, this.beanName);
	}

	try {
		return new TypedValue(beanResolver.resolve(state.getEvaluationContext(), this.beanName));
	}
	catch (AccessException ex) {
		throw new SpelEvaluationException(getStartPosition(), ex, SpelMessage.EXCEPTION_DURING_BEAN_RESOLUTION,
			this.beanName, ex.getMessage());
	}
}
 

@Override
public MethodExecutor resolve(EvaluationContext context, Object targetObject, String name, List<TypeDescriptor> arguments)
		throws AccessException {
	if (name.equals("hasRole")) {
		return new HasRoleExecutor(context.getTypeConverter());
	}
	return null;
}
 

@Override
public TypedValue read(final EvaluationContext context, final Object target, final String name)
    throws AccessException {
  try {
    return super.read(context, target, name);
  } catch (AccessException ae) {
    if (allowUnknownKeys) {
      return TypedValue.NULL;
    }
    throw ae;
  }
}
 

@Override
public boolean canWrite(EvaluationContext context, Object target, String name) throws AccessException {
	if (target == null) {
		return false;
	}
	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());
	PropertyCacheKey cacheKey = new PropertyCacheKey(type, name, target instanceof Class);
	if (this.writerCache.containsKey(cacheKey)) {
		return true;
	}
	Method method = findSetterForProperty(name, type, target);
	if (method != null) {
		// Treat it like a property
		Property property = new Property(type, null, method);
		TypeDescriptor typeDescriptor = new TypeDescriptor(property);
		this.writerCache.put(cacheKey, method);
		this.typeDescriptorCache.put(cacheKey, typeDescriptor);
		return true;
	}
	else {
		Field field = findField(name, type, target);
		if (field != null) {
			this.writerCache.put(cacheKey, field);
			this.typeDescriptorCache.put(cacheKey, new TypeDescriptor(field));
			return true;
		}
	}
	return false;
}
 

@Override
public TypedValue execute (EvaluationContext aContext, Object aTarget, Object... aArguments) throws AccessException {
  List<?> l1 = (List<?>) aArguments[0];
  List<?> l2 = (List<?>) aArguments[1];
  List<Object> joined = new ArrayList<>(l1.size()+l2.size());
  joined.addAll(l1);
  joined.addAll(l2);
  return new TypedValue(joined);
}
 

@Override
public TypedValue read(EvaluationContext context, @Nullable Object target, String name) throws AccessException {
	Object implicitVar = resolveImplicitVariable(name);
	if (implicitVar != null) {
		return new TypedValue(implicitVar);
	}
	return new TypedValue(this.pageContext.findAttribute(name));
}
 

private MethodExecutor findAccessorForMethod(List<TypeDescriptor> argumentTypes, Object targetObject,
		EvaluationContext evaluationContext) throws SpelEvaluationException {

	AccessException accessException = null;
	List<MethodResolver> methodResolvers = evaluationContext.getMethodResolvers();
	for (MethodResolver methodResolver : methodResolvers) {
		try {
			MethodExecutor methodExecutor = methodResolver.resolve(
					evaluationContext, targetObject, this.name, argumentTypes);
			if (methodExecutor != null) {
				return methodExecutor;
			}
		}
		catch (AccessException ex) {
			accessException = ex;
			break;
		}
	}

	String method = FormatHelper.formatMethodForMessage(this.name, argumentTypes);
	String className = FormatHelper.formatClassNameForMessage(
			targetObject instanceof Class ? ((Class<?>) targetObject) : targetObject.getClass());
	if (accessException != null) {
		throw new SpelEvaluationException(
				getStartPosition(), accessException, SpelMessage.PROBLEM_LOCATING_METHOD, method, className);
	}
	else {
		throw new SpelEvaluationException(getStartPosition(), SpelMessage.METHOD_NOT_FOUND, method, className);
	}
}
 

private TypeDescriptor getTypeDescriptor(EvaluationContext context, Object target, String name) {
	if (target == null) {
		return null;
	}
	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());

	if (type.isArray() && name.equals("length")) {
		return TypeDescriptor.valueOf(Integer.TYPE);
	}
	CacheKey cacheKey = new CacheKey(type, name, target instanceof Class);
	TypeDescriptor typeDescriptor = this.typeDescriptorCache.get(cacheKey);
	if (typeDescriptor == null) {
		// attempt to populate the cache entry
		try {
			if (canRead(context, target, name)) {
				typeDescriptor = this.typeDescriptorCache.get(cacheKey);
			}
			else if (canWrite(context, target, name)) {
				typeDescriptor = this.typeDescriptorCache.get(cacheKey);
			}
		}
		catch (AccessException ex) {
			// continue with null type descriptor
		}
	}
	return typeDescriptor;
}
 

/**
 * Decode the AccessException, throwing a lightweight evaluation exception or, if the
 * cause was a RuntimeException, throw the RuntimeException directly.
 */
private void throwSimpleExceptionIfPossible(Object value, AccessException ex) {
	if (ex.getCause() instanceof InvocationTargetException) {
		Throwable rootCause = ex.getCause().getCause();
		if (rootCause instanceof RuntimeException) {
			throw (RuntimeException) rootCause;
		}
		throw new ExpressionInvocationTargetException(getStartPosition(),
				"A problem occurred when trying to execute method '" + this.name +
				"' on object of type [" + value.getClass().getName() + "]", rootCause);
	}
}
 

@Override
public boolean canWrite(EvaluationContext context, Object target, String name) throws AccessException {
	if (target == null) {
		return false;
	}
	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());
	CacheKey cacheKey = new CacheKey(type, name, target instanceof Class);
	if (this.writerCache.containsKey(cacheKey)) {
		return true;
	}
	Method method = findSetterForProperty(name, type, target);
	if (method != null) {
		// Treat it like a property
		Property property = new Property(type, null, method);
		TypeDescriptor typeDescriptor = new TypeDescriptor(property);
		this.writerCache.put(cacheKey, method);
		this.typeDescriptorCache.put(cacheKey, typeDescriptor);
		return true;
	}
	else {
		Field field = findField(name, type, target);
		if (field != null) {
			this.writerCache.put(cacheKey, field);
			this.typeDescriptorCache.put(cacheKey, new TypeDescriptor(field));
			return true;
		}
	}
	return false;
}
 

private Object resolveImplicitVariable(String name) throws AccessException {
	if (this.variableResolver == null) {
		return null;
	}
	try {
		return this.variableResolver.resolveVariable(name);
	}
	catch (Exception ex) {
		throw new AccessException(
				"Unexpected exception occurred accessing '" + name + "' as an implicit variable", ex);
	}
}
 

@Override
public Object resolve(EvaluationContext context, String beanName)
		throws AccessException {
	if (beanName.equals("foo") || beanName.equals("bar")) {
		return new Spr9751_2();
	}
	throw new AccessException("not heard of "+beanName);
}
 

@Override
public TypedValue execute(EvaluationContext aContext, Object aTarget, Object... aArguments) throws AccessException {
  List<Integer> value = IntStream.rangeClosed((int)aArguments[0], (int)aArguments[1])
      .boxed()
      .collect(Collectors.toList());
  return new TypedValue(value);
}
 

@Override
public TypedValue execute (EvaluationContext aContext, Object aTarget, Object... aArguments) throws AccessException {
  String separator = (String) aArguments[0];
  List<?> values = (List<?>) aArguments[1];
  String str = values.stream()
                     .map(String::valueOf)
                     .collect(Collectors.joining(separator));
  return new TypedValue(str);
}
 

private TypeDescriptor getTypeDescriptor(EvaluationContext context, Object target, String name) {
	if (target == null) {
		return null;
	}
	Class<?> type = (target instanceof Class ? (Class<?>) target : target.getClass());

	if (type.isArray() && name.equals("length")) {
		return TypeDescriptor.valueOf(Integer.TYPE);
	}
	PropertyCacheKey cacheKey = new PropertyCacheKey(type, name, target instanceof Class);
	TypeDescriptor typeDescriptor = this.typeDescriptorCache.get(cacheKey);
	if (typeDescriptor == null) {
		// attempt to populate the cache entry
		try {
			if (canRead(context, target, name)) {
				typeDescriptor = this.typeDescriptorCache.get(cacheKey);
			}
			else if (canWrite(context, target, name)) {
				typeDescriptor = this.typeDescriptorCache.get(cacheKey);
			}
		}
		catch (AccessException ex) {
			// continue with null type descriptor
		}
	}
	return typeDescriptor;
}
 

@Override
public boolean canWrite(EvaluationContext context, Object target, String name) throws AccessException {
	return getMap(target).containsKey(name);
}
 

/**
 * Read-only: no-op.
 */
@Override
public void write(EvaluationContext context, @Nullable Object target, String name, @Nullable Object newValue)
		throws AccessException {
}
 

@Override
public boolean canWrite(EvaluationContext context, Object target, String name) throws AccessException {
  return false;
}
 

@Override
public TypedValue read(EvaluationContext context, @Nullable Object target, String name) throws AccessException {
	Assert.state(target instanceof BeanFactory, "Target must be of type BeanFactory");
	return new TypedValue(((BeanFactory) target).getBean(name));
}
 

@Override
public boolean canRead(EvaluationContext context, Object target, String name) throws AccessException {
	return (((Map<?, ?>) target).containsKey(name));
}
 

@Override
public TypedValue read(EvaluationContext context, Object target, String name) throws AccessException {
	return new TypedValue(((Map<?, ?>) target).get(name));
}