标签：相关 tor context 表达式 div argument result ssi birt
Spring Expression Language(Spring表达式语言)，用来解析java语言中的相关并获得反馈。
下面就摘录官方示例来简单描述一下。也作一下标记，方便以后查阅。
1 ExpressionParser parser = new SpelExpressionParser(); 2 Expression exp = parser.parseExpression("‘Hello World‘"); 3 String message = (String) exp.getValue();
变量message的值为：Hello World
1 ExpressionParser parser = new SpelExpressionParser(); 2 Expression exp = parser.parseExpression("‘Hello World‘.concat(‘!‘)"); 3 String message = (String) exp.getValue();
变量message的值为：Hello World!
1 ExpressionParser parser = new SpelExpressionParser(); 2 3 // invokes ‘getBytes()‘ 4 Expression exp = parser.parseExpression("‘Hello World‘.bytes"); 5 byte[] bytes = (byte[]) exp.getValue();
1 ExpressionParser parser = new SpelExpressionParser(); 2 3 // invokes ‘getBytes().length‘ 4 Expression exp = parser.parseExpression("‘Hello World‘.bytes.length"); 5 int length = (Integer) exp.getValue();
1 ExpressionParser parser = new SpelExpressionParser(); 2 Expression exp = parser.parseExpression("new String(‘hello world‘).toUpperCase()"); 3 String message = exp.getValue(String.class);
1 // Create and set a calendar 2 GregorianCalendar c = new GregorianCalendar(); 3 c.set(1856, 7, 9); 4 5 // The constructor arguments are name, birthday, and nationality. 6 Inventor tesla = new Inventor("Nikola Tesla", c.getTime(), "Serbian"); 7 8 ExpressionParser parser = new SpelExpressionParser(); 9 Expression exp = parser.parseExpression("name"); 10 11 EvaluationContext context = new StandardEvaluationContext(tesla); 12 String name = (String) exp.getValue(context);
获取对象tesla的属性name的值。
1 / Create and set a calendar 2 GregorianCalendar c = new GregorianCalendar(); 3 c.set(1856, 7, 9); 4 5 // The constructor arguments are name, birthday, and nationality. 6 Inventor tesla = new Inventor("Nikola Tesla", c.getTime(), "Serbian"); 7 8 ExpressionParser parser = new SpelExpressionParser(); 9 Expression exp = parser.parseExpression("name == ‘Nikola Tesla‘"); 10 boolean result = exp.getValue(context, Boolean.class); // evaluates to true
变量result为判断对象tesla的属性name是否和字符串‘Nikola Tesla‘相同。
Spring文档苦读【7】【Spring Expression Language（SpEL）】
标签：相关 tor context 表达式 div argument result ssi birt
原文地址：http://www.cnblogs.com/may-cn/p/6234483.html
