javax.servlet.jsp.el
类 Expression

java.lang.Object
  javax.servlet.jsp.el.Expression

已过时。 As of JSP 2.1, replaced by ValueExpression

public abstract class Expression
extends Object

The abstract class for a prepared expression.

An instance of an Expression can be obtained via from an ExpressionEvaluator instance.

An Expression may or not have done a syntactic parse of the expression. A client invoking the evaluate() method should be ready for the case where ELParseException exceptions are raised.

从以下版本开始：

JSP 2.0

构造方法摘要

Expression()
已过时。

方法摘要

abstract Object

evaluate(VariableResolver vResolver) 已过时。 Evaluates an expression that was previously prepared.

从类 java.lang.Object 继承的方法

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造方法详细信息

Expression

public Expression()

已过时。

方法详细信息

evaluate

public abstract Object evaluate(VariableResolver vResolver)
                         throws ELException

已过时。

Evaluates an expression that was previously prepared. In some implementations preparing an expression involves full syntactic validation, but others may not do so. Evaluating the expression may raise an ELParseException as well as other ELExceptions due to run-time evaluation.

参数：

vResolver - A VariableResolver instance that can be used at runtime to resolve the name of implicit objects into Objects.

返回：

The result of the expression evaluation.

抛出：

ELException - Thrown if the expression evaluation failed.