Java ExpressionParser类代码示例

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Override
public Map<String, String> getUserInfos(User user, HttpServletRequest request, final Map<String, String> userInfosInComputing) {
	
	Map<String, String> userInfos = new HashMap<String, String>(); 
	for(String name: sgcParam2spelExp.keySet()) {
		String expression = sgcParam2spelExp.get(name);
		ExpressionParser parser = new SpelExpressionParser();
		Expression exp = parser.parseExpression(expression);

		EvaluationContext context = new StandardEvaluationContext();
		context.setVariable("user", user);
		context.setVariable("request", request);
		context.setVariable("userInfosInComputing", userInfosInComputing);
		context.setVariable("dateUtils", dateUtils);
		
		String value = (String) exp.getValue(context);
		userInfos.put(name, value);
	}
	return userInfos;
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
/**
 * Creates the key filter lambda which is responsible to decide how the rate limit will be performed. The key
 * is the unique identifier like an IP address or a username.
 * 
 * @param url is used to generated a unique cache key
 * @param rateLimit the {@link RateLimit} configuration which holds the skip condition string
 * @param expressionParser is used to evaluate the expression if the filter key type is EXPRESSION.
 * @param beanFactory used to get full access to all java beans in the SpEl
 * @return should not been null. If no filter key type is matching a plain 1 is returned so that all requests uses the same key.
 */
public KeyFilter getKeyFilter(String url, RateLimit rateLimit, ExpressionParser expressionParser, BeanFactory beanFactory) {
	
	switch(rateLimit.getFilterKeyType()) {
	case IP:
		return (request) -> url + "-" + request.getRemoteAddr();
	case EXPRESSION:
		String expression = rateLimit.getExpression();
		if(StringUtils.isEmpty(expression)) {
			throw new MissingKeyFilterExpressionException();
		}
		StandardEvaluationContext context = new StandardEvaluationContext();
		context.setBeanResolver(new BeanFactoryResolver(beanFactory));
		return  (request) -> {
			//TODO performance problem - how can the request object reused in the expression without setting it as a rootObject
			Expression expr = expressionParser.parseExpression(rateLimit.getExpression()); 
			final String value = expr.getValue(context, request, String.class);
			return url + "-" + value;
		};
	
	}
	return (request) -> url + "-" + "1";
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
/**
 * Creates the lambda for the skip condition which will be evaluated on each request
 * 
 * @param rateLimit the {@link RateLimit} configuration which holds the skip condition string
 * @param expressionParser is used to evaluate the skip expression
 * @param beanFactory used to get full access to all java beans in the SpEl
 * @return the lamdba condition which will be evaluated lazy - null if there is no condition available.
 */
public Condition skipCondition(RateLimit rateLimit, ExpressionParser expressionParser, BeanFactory beanFactory) {
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.setBeanResolver(new BeanFactoryResolver(beanFactory));
	
	if(rateLimit.getSkipCondition() != null) {
		return  (request) -> {
			Expression expr = expressionParser.parseExpression(rateLimit.getSkipCondition()); 
			Boolean value = expr.getValue(context, request, Boolean.class);
			return value;
		};
	}
	return null;
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void testRootObject() throws Exception {
	GregorianCalendar c = new GregorianCalendar();
	c.set(1856, 7, 9);

	//  The constructor arguments are name, birthday, and nationaltiy.
	Inventor tesla = new Inventor("Nikola Tesla", c.getTime(), "Serbian");

	ExpressionParser parser = new SpelExpressionParser();
	Expression exp = parser.parseExpression("name");

	StandardEvaluationContext context = new StandardEvaluationContext();
	context.setRootObject(tesla);

	String name = (String) exp.getValue(context);
	assertEquals("Nikola Tesla",name);
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void testLiterals() throws Exception {
	ExpressionParser parser = new SpelExpressionParser();

	String helloWorld = (String) parser.parseExpression("'Hello World'").getValue(); // evals to "Hello World"
	assertEquals("Hello World",helloWorld);

	double avogadrosNumber  = (Double) parser.parseExpression("6.0221415E+23").getValue();
	assertEquals(6.0221415E+23, avogadrosNumber, 0);

	int maxValue = (Integer) parser.parseExpression("0x7FFFFFFF").getValue();  // evals to 2147483647
	assertEquals(Integer.MAX_VALUE,maxValue);

	boolean trueValue = (Boolean) parser.parseExpression("true").getValue();
	assertTrue(trueValue);

	Object nullValue = parser.parseExpression("null").getValue();
	assertNull(nullValue);
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@SuppressWarnings("unchecked")
@Test
public void testSpecialVariables() throws Exception {
	// create an array of integers
	List<Integer> primes = new ArrayList<Integer>();
	primes.addAll(Arrays.asList(2,3,5,7,11,13,17));

	// create parser and set variable 'primes' as the array of integers
	ExpressionParser parser = new SpelExpressionParser();
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.setVariable("primes",primes);

	// all prime numbers > 10 from the list (using selection ?{...})
	List<Integer> primesGreaterThanTen = (List<Integer>) parser.parseExpression("#primes.?[#this>10]").getValue(context);
	assertEquals("[11, 13, 17]",primesGreaterThanTen.toString());
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void testCreateListsOnAttemptToIndexNull01() throws EvaluationException, ParseException {
	ExpressionParser parser = new SpelExpressionParser(new SpelParserConfiguration(true, true));
	Expression expression = parser.parseExpression("list[0]");
	TestClass testClass = new TestClass();
	Object o = null;
	o = expression.getValue(new StandardEvaluationContext(testClass));
	assertEquals("", o);
	o = parser.parseExpression("list[3]").getValue(new StandardEvaluationContext(testClass));
	assertEquals("", o);
	assertEquals(4, testClass.list.size());
	try {
		o = parser.parseExpression("list2[3]").getValue(new StandardEvaluationContext(testClass));
		fail();
	} catch (EvaluationException ee) {
		ee.printStackTrace();
		// success!
	}
	o = parser.parseExpression("foo[3]").getValue(new StandardEvaluationContext(testClass));
	assertEquals("", o);
	assertEquals(4, testClass.getFoo().size());
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
/**
 * SPR-6984: attempting to index a collection on write using an index that
 * doesn't currently exist in the collection (address.crossStreets[0] below)
 */
@Test
public void initializingCollectionElementsOnWrite() throws Exception {
	TestPerson person = new TestPerson();
	EvaluationContext context = new StandardEvaluationContext(person);
	SpelParserConfiguration config = new SpelParserConfiguration(true, true);
	ExpressionParser parser = new SpelExpressionParser(config);
	Expression expression = parser.parseExpression("name");
	expression.setValue(context, "Oleg");
	assertEquals("Oleg", person.getName());

	expression = parser.parseExpression("address.street");
	expression.setValue(context, "123 High St");
	assertEquals("123 High St", person.getAddress().getStreet());

	expression = parser.parseExpression("address.crossStreets[0]");
	expression.setValue(context, "Blah");
	assertEquals("Blah", person.getAddress().getCrossStreets().get(0));

	expression = parser.parseExpression("address.crossStreets[3]");
	expression.setValue(context, "Wibble");
	assertEquals("Blah", person.getAddress().getCrossStreets().get(0));
	assertEquals("Wibble", person.getAddress().getCrossStreets().get(3));
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void incdecTogether() {
	Spr9751 helper = new Spr9751();
	StandardEvaluationContext ctx = new StandardEvaluationContext(helper);
	ExpressionParser parser = new SpelExpressionParser(new SpelParserConfiguration(true, true));
	Expression e = null;

	// index1 is 2 at the start - the 'intArray[#root.index1++]' should not be evaluated twice!
	// intArray[2] is 3
	e = parser.parseExpression("intArray[#root.index1++]++");
	e.getValue(ctx,Integer.class);
	assertEquals(3,helper.index1);
	assertEquals(4,helper.intArray[2]);

	// index1 is 3 intArray[3] is 4
	e =  parser.parseExpression("intArray[#root.index1++]--");
	assertEquals(4,e.getValue(ctx,Integer.class).intValue());
	assertEquals(4,helper.index1);
	assertEquals(3,helper.intArray[3]);

	// index1 is 4, intArray[3] is 3
	e =  parser.parseExpression("intArray[--#root.index1]++");
	assertEquals(3,e.getValue(ctx,Integer.class).intValue());
	assertEquals(3,helper.index1);
	assertEquals(4,helper.intArray[3]);
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void testGetValuePerformance() throws Exception {
	Assume.group(TestGroup.PERFORMANCE);
	Map<String, String> map = new HashMap<String, String>();
	map.put("key", "value");
	EvaluationContext context = new StandardEvaluationContext(map);

	ExpressionParser spelExpressionParser = new SpelExpressionParser();
	Expression expr = spelExpressionParser.parseExpression("#root['key']");

	StopWatch s = new StopWatch();
	s.start();
	for (int i = 0; i < 10000; i++) {
		expr.getValue(context);
	}
	s.stop();
	assertThat(s.getTotalTimeMillis(), lessThan(200L));
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
/**
 * We add property accessors in the order:
 * First, Second, Third, Fourth.
 * They are not utilized in this order; preventing a priority or order of operations
 * in evaluation of SPEL expressions for a given context.
 */
@Test
public void propertyAccessorOrder_8211() {
	ExpressionParser expressionParser = new SpelExpressionParser();
	StandardEvaluationContext evaluationContext = new StandardEvaluationContext(new ContextObject());

	evaluationContext.addPropertyAccessor(new TestPropertyAccessor("firstContext"));
	evaluationContext.addPropertyAccessor(new TestPropertyAccessor("secondContext"));
	evaluationContext.addPropertyAccessor(new TestPropertyAccessor("thirdContext"));
	evaluationContext.addPropertyAccessor(new TestPropertyAccessor("fourthContext"));

	assertEquals("first", expressionParser.parseExpression("shouldBeFirst").getValue(evaluationContext));
	assertEquals("second", expressionParser.parseExpression("shouldBeSecond").getValue(evaluationContext));
	assertEquals("third", expressionParser.parseExpression("shouldBeThird").getValue(evaluationContext));
	assertEquals("fourth", expressionParser.parseExpression("shouldBeFourth").getValue(evaluationContext));
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
/**
 * Test the ability to subclass the ReflectiveMethodResolver and change how it
 * determines the set of methods for a type.
 */
@Test
public void customStaticFunctions_SPR9038() {
	ExpressionParser parser = new SpelExpressionParser();
	StandardEvaluationContext context = new StandardEvaluationContext();
	List<MethodResolver> methodResolvers = new ArrayList<MethodResolver>();
	methodResolvers.add(new ReflectiveMethodResolver() {
		@Override
		protected Method[] getMethods(Class<?> type) {
			try {
				return new Method[] {
						Integer.class.getDeclaredMethod("parseInt", new Class<?>[] {String.class, Integer.TYPE})};
			}
			catch (NoSuchMethodException ex) {
				return new Method[0];
			}
		}
	});

	context.setMethodResolvers(methodResolvers);
	Expression expression = parser.parseExpression("parseInt('-FF', 16)");

	Integer result = expression.getValue(context, "", Integer.class);
	assertEquals(-255, result.intValue());
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void SPR10452() throws Exception {
	SpelParserConfiguration configuration = new SpelParserConfiguration(false, false);
	ExpressionParser parser = new SpelExpressionParser(configuration);

	StandardEvaluationContext context = new StandardEvaluationContext();
	Expression spel = parser.parseExpression("#enumType.values()");

	context.setVariable("enumType", ABC.class);
	Object result = spel.getValue(context);
	assertNotNull(result);
	assertTrue(result.getClass().isArray());
	assertEquals(ABC.A, Array.get(result, 0));
	assertEquals(ABC.B, Array.get(result, 1));
	assertEquals(ABC.C, Array.get(result, 2));

	context.setVariable("enumType", XYZ.class);
	result = spel.getValue(context);
	assertNotNull(result);
	assertTrue(result.getClass().isArray());
	assertEquals(XYZ.X, Array.get(result, 0));
	assertEquals(XYZ.Y, Array.get(result, 1));
	assertEquals(XYZ.Z, Array.get(result, 2));
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
@Test
public void SPR9735() {
	Item item = new Item();
	item.setName("parent");

	Item item1 = new Item();
	item1.setName("child1");

	Item item2 = new Item();
	item2.setName("child2");

	item.add(item1);
	item.add(item2);

	ExpressionParser parser = new SpelExpressionParser();
	EvaluationContext context = new StandardEvaluationContext();
	Expression exp = parser.parseExpression("#item[0].name");
	context.setVariable("item", item);

	assertEquals("child1", exp.getValue(context));
}
 

import org.springframework.expression.ExpressionParser; //导入依赖的package包/类
/**
 * 通过spring spel解析参数获取redis缓存key
 * 
 * @param keys
 *            缓存keys
 * @param paramNames
 *            参数名
 * @param args
 *            参数列表
 * @return
 */
public static String parseKeyByParam(String keys, String[] paramNames, Object[] args) {
	if (StringUtils.isBlank(keys)) {
		return "";
	}
	ExpressionParser parser = getParser();
	StandardEvaluationContext context = new StandardEvaluationContext();
	// 把方法参数放入SPEL上下文中
	for (int i = 0; i < paramNames.length; i++) {
		context.setVariable(paramNames[i], args[i]);
	}
	// 获取参数key
	StringBuffer sb = new StringBuffer();
	// for (int i = 0; i < keys.length; i++) {
	sb.append(parser.parseExpression(keys).getValue(context, String.class));
	// }
	return sb.toString();
}