[英]Passing a Enum value as a parameter from JSF (revisited)
Passing a Enum value as a parameter from JSF 将Enum值作为参数从JSF传递
This question already deals with this issue, however the proposed solution has not worked for me. 这个问题已经解决了这个问题,但是提出的解决方案并没有对我有用。 I define the following enumeration in my backing bean: 我在我的支持bean中定义了以下枚举:
public enum QueryScope {
SUBMITTED("Submitted by me"), ASSIGNED("Assigned to me"), ALL("All items");
private final String description;
public String getDescription() {
return description;
}
QueryScope(String description) {
this.description = description;
}
}
Then I use it as a method parameter 然后我用它作为方法参数
public void test(QueryScope scope) {
// do something
}
And use it via EL in my JSF page 并在我的JSF页面中通过EL使用它
<h:commandButton
id = "commandButton_test"
value = "Testing enumerations"
action = "#{backingBean.test('SUBMITTED')}" />
So far so good - identical to the problem posed in the original question. 到目前为止一直很好 - 与原始问题中提出的问题相同。 However I have to deal with a javax.servlet.ServletException: Method not found: %fully_qualified_package_name%.BackingBean.test(java.lang.String)
. 但是我必须处理javax.servlet.ServletException: Method not found: %fully_qualified_package_name%.BackingBean.test(java.lang.String)
。
So it seems that JSF is interpreting the method call as if I would like to call a method with String as parameter type (which of course does not exist) - therefore no implicit conversion takes place. 所以似乎JSF正在解释方法调用,好像我想调用一个String作为参数类型的方法(当然不存在) - 因此不会发生隐式转换。
What could be the factor that makes the behavior differ in this example from the aforelinked? 可能是什么因素导致这个例子的行为与前面提到的不同?
In your backingBean
, you may have written a method with the enum
parameter: 在backingBean
,您可能已经使用enum
参数编写了一个方法:
<!-- This won't work, EL doesn't support Enum: -->
<h:commandButton ... action="#{backingBean.test(QueryScope.SUBMITTED)}" />
// backingBean:
public void test(QueryScope queryScope) {
// your impl
}
But, the proposed solution
does not use enum, it uses String
. 但是, proposed solution
不使用枚举,它使用String
。 That's because EL doesn't support enum at all: 那是因为EL根本不支持enum:
<!-- This will work, EL does support String: -->
<h:commandButton ... action="#{backingBean.test('SUBMITTED')}" />
// backingBean:
public void test(String queryScopeString) {
QueryScope queryScope = QueryScope.valueOf(queryScopeString);
// your impl
}
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