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1 問題描述 
mybatis3.2.x版本，做壓力測試，併發200使用者，出現瞭如下異常.

1. org.apache.ibatis.builder.BuilderException: Error evaluating expression 'size() > 0'. Cause: org.apache.ibatis.ognl.MethodFailedException: Method "size" failed for object [one, two] [java.lang.IllegalAccessException: Class org.apache.ibatis.ognl.OgnlRuntime can not access a member of class java.util.Collections$UnmodifiableCollection with modifiers "public"]

2. at org.apache.ibatis.scripting.xmltags.OgnlCache.getValue(OgnlCache.java:47)

3. at org.apache.ibatis.scripting.xmltags.ExpressionEvaluator.evaluateBoolean(ExpressionEvaluator.java:29)

4. at OgnlConcurrentTest$1.run(OgnlConcurrentTest.java:51)

5. at java.lang.Thread.run(Thread.java:745)

6. Caused by: org.apache.ibatis.ognl.MethodFailedException: Method "size" failed for object [one, two] [java.lang.IllegalAccessException: Class org.apache.ibatis.ognl.OgnlRuntime can not access a member of class java.util.Collections$UnmodifiableCollection with modifiers "public"]

7. at org.apache.ibatis.ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:837)

8. at org.apache.ibatis.ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:61)

9. at org.apache.ibatis.ognl.OgnlRuntime.callMethod(OgnlRuntime.java:860)

10. at org.apache.ibatis.ognl.ASTMethod.getValueBody(ASTMethod.java:73)

11. at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)

2 解決方案 

在網上搜了一桶，找到原因是mybatis3.2.x版本引用ognl的版本為2.6.9，出問題的地方程式碼如下。Modifier.isPublic存在問題，好在ognl2.7版本已經修復,故將mybatis版本升級到mybatis3.3.x以上，同時升級mybatis-spring到1.3.x以上即可。 
因為mybatis-spring1.2.x引用的mybatis版本還是mybatis3.2.x，故需要升級。 

1. public static Object invokeMethod(Object target, Method method, Object[] argsArray)

2. throws InvocationTargetException, IllegalAccessException

3. {

4. boolean wasAccessible = true;

5.  

6. if (securityManager != null) {

7. try {

8. securityManager.checkPermission(getPermission(method));

9. } catch (SecurityException ex) {

10. throw new IllegalAccessException("Method [" + method + "] cannot be accessed.");

11. }

12. }

13. if (((!Modifier.isPublic(method.getModifiers())) || (!Modifier.isPublic(method.getDeclaringClass().getModifiers()))) &&

14. (!(wasAccessible = method.isAccessible()))) {

15. method.setAccessible(true);

16. }

17.  

18. Object result = method.invoke(target, argsArray);

19. if (!wasAccessible) {

20. method.setAccessible(false);

21. }

22. return result;

23. }

參考資料 

MyBatis 3.2.x版本在併發情況下可能出現的b