See {@link #isSpringJspExpressionSupportActive} for guidelines
+ * on when to use Spring's JSP expression support as opposed to the
+ * built-in expression support in JSP 2.0+ containers.
+ *
* @author Juergen Hoeller
* @author Alef Arendsen
* @since 11.07.2003
@@ -37,11 +42,42 @@ import org.springframework.util.Assert;
*/
public abstract class ExpressionEvaluationUtils {
+ /**
+ * Expression support parameter at the servlet context level
+ * (i.e. a context-param in web.xml): "springJspExpressionSupport".
+ */
+ public static final String EXPRESSION_SUPPORT_CONTEXT_PARAM = "springJspExpressionSupport";
+
public static final String EXPRESSION_PREFIX = "${";
public static final String EXPRESSION_SUFFIX = "}";
+ /**
+ * Check whether Spring's JSP expression support is actually active.
+ *
Note that JSP 2.0+ containers come with expression support themselves:
+ * However, it will only be active for web applications declaring Servlet 2.4
+ * or higher in their web.xml deployment descriptor.
+ *
If a web.xml context-param named "springJspExpressionSupport" is
+ * found, its boolean value will be taken to decide whether this support is active.
+ * If not found, for backwards compatibility with Servlet 2.3 applications,
+ * Spring's expression support will remain active by default.
+ *
Recommendations: Explicitly set "springJspExpressionSupport" to "false"
+ * in order to prevent double evaluation for Servlet 2.4+ based applications.
+ * @param pageContext current JSP PageContext
+ * @return true if active (ExpressionEvaluationUtils will actually evaluate expressions);
+ * false if not active (ExpressionEvaluationUtils will return given values as-is,
+ * relying on the JSP container pre-evaluating values before passing them to JSP tag attributes)
+ */
+ public static boolean isSpringJspExpressionSupportActive(PageContext pageContext) {
+ ServletContext sc = pageContext.getServletContext();
+ String springJspExpressionSupport = sc.getInitParameter(EXPRESSION_SUPPORT_CONTEXT_PARAM);
+ if (springJspExpressionSupport != null) {
+ return Boolean.valueOf(springJspExpressionSupport);
+ }
+ return true;
+ }
+
/**
* Check if the given expression value is an EL expression.
* @param value the expression to check
@@ -67,7 +103,7 @@ public abstract class ExpressionEvaluationUtils {
public static Object evaluate(String attrName, String attrValue, Class resultClass, PageContext pageContext)
throws JspException {
- if (isExpressionLanguage(attrValue)) {
+ if (isSpringJspExpressionSupportActive(pageContext) && isExpressionLanguage(attrValue)) {
return doEvaluate(attrName, attrValue, resultClass, pageContext);
}
else if (attrValue != null && resultClass != null && !resultClass.isInstance(attrValue)) {
@@ -90,7 +126,7 @@ public abstract class ExpressionEvaluationUtils {
public static Object evaluate(String attrName, String attrValue, PageContext pageContext)
throws JspException {
- if (isExpressionLanguage(attrValue)) {
+ if (isSpringJspExpressionSupportActive(pageContext) && isExpressionLanguage(attrValue)) {
return doEvaluate(attrName, attrValue, Object.class, pageContext);
}
else {
@@ -109,7 +145,7 @@ public abstract class ExpressionEvaluationUtils {
public static String evaluateString(String attrName, String attrValue, PageContext pageContext)
throws JspException {
- if (isExpressionLanguage(attrValue)) {
+ if (isSpringJspExpressionSupportActive(pageContext) && isExpressionLanguage(attrValue)) {
return (String) doEvaluate(attrName, attrValue, String.class, pageContext);
}
else {
@@ -128,7 +164,7 @@ public abstract class ExpressionEvaluationUtils {
public static int evaluateInteger(String attrName, String attrValue, PageContext pageContext)
throws JspException {
- if (isExpressionLanguage(attrValue)) {
+ if (isSpringJspExpressionSupportActive(pageContext) && isExpressionLanguage(attrValue)) {
return (Integer) doEvaluate(attrName, attrValue, Integer.class, pageContext);
}
else {
@@ -147,7 +183,7 @@ public abstract class ExpressionEvaluationUtils {
public static boolean evaluateBoolean(String attrName, String attrValue, PageContext pageContext)
throws JspException {
- if (isExpressionLanguage(attrValue)) {
+ if (isSpringJspExpressionSupportActive(pageContext) && isExpressionLanguage(attrValue)) {
return (Boolean) doEvaluate(attrName, attrValue, Boolean.class, pageContext);
}
else {
@@ -155,7 +191,6 @@ public abstract class ExpressionEvaluationUtils {
}
}
-
/**
* Actually evaluate the given expression (be it EL or a literal String value)
* to an Object of a given type. Supports concatenated expressions,
diff --git a/org.springframework.web/src/test/java/org/springframework/web/util/ExpressionEvaluationUtilsTests.java b/org.springframework.web/src/test/java/org/springframework/web/util/ExpressionEvaluationUtilsTests.java
index ab38e51888..5f030dd0e1 100644
--- a/org.springframework.web/src/test/java/org/springframework/web/util/ExpressionEvaluationUtilsTests.java
+++ b/org.springframework.web/src/test/java/org/springframework/web/util/ExpressionEvaluationUtilsTests.java
@@ -1,5 +1,5 @@
/*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -24,18 +24,31 @@ import javax.servlet.jsp.el.ExpressionEvaluator;
import javax.servlet.jsp.el.FunctionMapper;
import javax.servlet.jsp.el.VariableResolver;
-import junit.framework.TestCase;
+import org.junit.Test;
import org.springframework.mock.web.MockExpressionEvaluator;
import org.springframework.mock.web.MockPageContext;
+import org.springframework.mock.web.MockServletContext;
+
+import static org.junit.Assert.*;
/**
* @author Aled Arendsen
* @author Juergen Hoeller
* @since 16.09.2003
*/
-public class ExpressionEvaluationUtilsTests extends TestCase {
+public class ExpressionEvaluationUtilsTests {
+ @Test
+ public void testIsSpringJspExpressionSupportActive() {
+ MockServletContext sc = new MockServletContext();
+ PageContext pc = new MockPageContext(sc);
+ assertTrue(ExpressionEvaluationUtils.isSpringJspExpressionSupportActive(pc));
+ sc.addInitParameter("springJspExpressionSupport", "false");
+ assertFalse(ExpressionEvaluationUtils.isSpringJspExpressionSupportActive(pc));
+ }
+
+ @Test
public void testIsExpressionLanguage() {
assertTrue(ExpressionEvaluationUtils.isExpressionLanguage("${bla}"));
assertTrue(ExpressionEvaluationUtils.isExpressionLanguage("bla${bla}"));
@@ -43,6 +56,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
assertFalse(ExpressionEvaluationUtils.isExpressionLanguage("bla$b{"));
}
+ @Test
public void testEvaluate() throws Exception {
PageContext ctx = new MockPageContext();
ctx.setAttribute("bla", "blie");
@@ -59,6 +73,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
}
}
+ @Test
public void testEvaluateWithConcatenation() throws Exception {
PageContext ctx = new MockPageContext();
ctx.setAttribute("bla", "blie");
@@ -98,6 +113,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
}
}
+ @Test
public void testEvaluateString() throws Exception {
PageContext ctx = new MockPageContext();
ctx.setAttribute("bla", "blie");
@@ -106,6 +122,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
assertEquals("blie", ExpressionEvaluationUtils.evaluateString("test", "blie", ctx));
}
+ @Test
public void testEvaluateStringWithConcatenation() throws Exception {
PageContext ctx = new MockPageContext();
ctx.setAttribute("bla", "blie");
@@ -137,6 +154,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
}
+ @Test
public void testEvaluateInteger() throws Exception {
PageContext ctx = new MockPageContext();
ctx.setAttribute("bla", new Integer(1));
@@ -145,6 +163,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
assertEquals(21, ExpressionEvaluationUtils.evaluateInteger("test", "21", ctx));
}
+ @Test
public void testEvaluateBoolean() throws Exception {
PageContext ctx = new MockPageContext();
ctx.setAttribute("bla", new Boolean(true));
@@ -153,6 +172,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
assertTrue(ExpressionEvaluationUtils.evaluateBoolean("test", "true", ctx));
}
+ @Test
public void testRepeatedEvaluate() throws Exception {
PageContext ctx = new CountingMockPageContext();
CountingMockExpressionEvaluator eval = (CountingMockExpressionEvaluator) ctx.getExpressionEvaluator();
@@ -172,6 +192,7 @@ public class ExpressionEvaluationUtilsTests extends TestCase {
assertEquals(4, eval.evaluateCount);
}
+ @Test
public void testEvaluateWithComplexConcatenation() throws Exception {
PageContext ctx = new CountingMockPageContext();
CountingMockExpressionEvaluator eval = (CountingMockExpressionEvaluator) ctx.getExpressionEvaluator();