Struts Learning type Conversion

* Get the corresponding content from the page
* In action class action, declare a property with the same name as the value of the form Name property on the page
* provides get and set methods
* The STRUTS2 framework takes the corresponding content from the page through a reflection mechanism
* The STRUTS2 framework cannot convert a string type obtained from a page into any type
* Custom type converters are required when the STRUTS2 framework does not convert the string types obtained in the page
* Custom type converters:
* Either implement the TypeConverter interface or inherit an implementation class from the TypeConverter interface, we inherit the Defaulttypeconverter class
* Override Convertvalue (Object value, Class totype) {} method
* parameter "value": the value to convert
* parameter "ToType": Type to convert
* Specific code implementation:
if (value==null) {
return false;
            }
if (totype==null) {
return false;
            }
if (totype!=java.util.date.class) {
return false;
            }
if (value instanceof java.lang.string[]) {
String [] str = (string[]) value;
if (str[0]!=null&&str[0].length () >0) {
try {
SimpleDateFormat sdf = new SimpleDateFormat ("Yyyy/mm/dd");
return Sdf.parse (Str[0]);
} catch (ParseException e) {
                        /*
* In the STRUTS2 framework, the custom type converter,
* If we do not throw exceptions manually, the STRUTS2 framework catches only exceptions, but does not throw them.
* So the framework will assume that the conversion of the type converter succeeds to the successful page.
                         */
throw new RuntimeException (e);
                    }
                }
            }
* Two ways of registering:
* Field-based (local)
* Create a resource file named "Useraction-conversion.properties" in the same directory as Action class action
* Useraction is the name of the Action class action
* "-conversion.properties" is a fixed notation
* Its content is configured as follows:
Createtime=cn.swust.converter.dateconverter(Field name = Full class name of the custom converter)
* Class-based (global)
* Under the SRC directory, create a resource file named "Xwork-conversion.properties"
* The name of the resource file is fixed
* Its content is configured as follows:
Java.util.date=cn.swust.converter.dateconverter
* If you enter an incorrect value in the page, do not manually throw an exception, the page will still be turned to a successful page
            /*
* In the STRUTS2 framework, the custom type converter,
* If we do not throw exceptions manually, the STRUTS2 framework catches only exceptions, but does not throw them.
* So the framework will assume that the conversion of the type converter succeeds to the successful page.
             */
* Configuration Modification error message is Chinese
* Create a resource file named "Converter.properties" in the same directory as Action class action
* The resource file is configured as follows:
* For all fields:
xwork.default.invalid.fieldvalue= type conversion failed ' {0} '.
* For a field:
invalid.fieldvalue.createtime= Date of birth conversion failed
* Configuration in Struts.xml file:
<constant name= "Struts.custom.i18n.resources"
value= "Cn.swust.converter.converter" >
</constant>

Struts Learning type Conversion