自定義Spring EL解析

    @Test
    public void test() {
    	//數據
        Properties properties = new Properties();
        properties.put("text", "hello world");
        properties.put("timeout", "#{30 * 1000L}");
        properties.put("random", "${random.int}");

		//數據源
        MutablePropertySources propertySources = new MutablePropertySources();
        propertySources.addLast(new PropertiesPropertySource("default", properties));
        propertySources.addLast(new RandomValuePropertySource());

		//屬性解析
        PropertySourcesPropertyResolver propertyResolver = new PropertySourcesPropertyResolver(propertySources);

		//表達式解析
        StandardBeanExpressionResolver expressionResolver = new StandardBeanExpressionResolver();
        DefaultListableBeanFactory factory = new DefaultListableBeanFactory();

		//類型轉換
        SimpleTypeConverter typeConverter = new SimpleTypeConverter();

        String textProp = propertyResolver.resolveRequiredPlaceholders("${text}");
        Object textObj = expressionResolver.evaluate(textProp, new BeanExpressionContext(factory, null));
        String text = typeConverter.convertIfNecessary(textObj, String.class);
        System.out.println(text);

        String timeoutProp = propertyResolver.resolveRequiredPlaceholders("${timeout}");
        Object timeoutObj = expressionResolver.evaluate(timeoutProp, new BeanExpressionContext(factory, null));
        Long timeout = typeConverter.convertIfNecessary(timeoutObj, Long.class);
        System.out.println(timeout);

        String randomProp = propertyResolver.resolveRequiredPlaceholders("${random}");
        Object randomObj = expressionResolver.evaluate(randomProp, new BeanExpressionContext(factory, null));
        Integer random = typeConverter.convertIfNecessary(randomObj, Integer.class);
        System.out.println(random);
    }