springMVC类型转换，@initBinder使用

http://jwlsky.iteye.com/blog/18906761：代码实例Java代码@InitBinderpublic void initBinder(WebDataBinder binder) {SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");dateFormat.setLenient(false);binder.registerCustomEditor(Date.class,new CustomDateEditor(dateFormat,true));binder.registerCustomEditor(SystemInfo.class,new PropertyEditorSupport() {@Overridepublic void setAsText(String text)throws IllegalArgumentException {if (!StringUtils.hasText(text)) {return;}{Long systemInfoId = Long.valueOf(text);SystemInfo systemInfo = systemInfoService.findById(systemInfoId);setValue(systemInfo);}}});binder.registerCustomEditor(Category.class,new PropertyEditorSupport() {@Overridepublic void setAsText(String text)throws IllegalArgumentException {if (!StringUtils.hasText(text)) {return;} else {Long categoryId = Long.valueOf(text);Category category = categoryService.findById(categoryId);setValue(category);}}});}

@InitBinder
public void initBinder(WebDataBinder binder) {

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
dateFormat.setLenient(false);
binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));

binder.registerCustomEditor(SystemInfo.class, new PropertyEditorSupport() {

@Override
public void setAsText(String text) throws IllegalArgumentException {
if (!StringUtils.hasText(text)) {
return;
}
{
Long systemInfoId = Long.valueOf(text);
SystemInfo systemInfo = systemInfoService.findById(systemInfoId);
setValue(systemInfo);
}
}
});

binder.registerCustomEditor(Category.class, new PropertyEditorSupport() {

@Override
public void setAsText(String text) throws IllegalArgumentException {
if (!StringUtils.hasText(text)) {
return;
} else {
Long categoryId = Long.valueOf(text);
Category category = categoryService.findById(categoryId);
setValue(category);
}
}
});
}

Html代码<form:formmodelAttribute="categoryEditForm"id="categoryForm"method="post"action="saveOrUpdate.do"><form:hiddenpath="category.objectId"/><inputtype="hidden"name="category.parent"value="${categoryEditForm.category.parent.objectId}"/><inputtype="hidden"name="category.systemInfo"value="${categoryEditForm.category.systemInfo.objectId }"/><divclass="area"><divclass="areaTitle"><divclass="inner"><label>Category Information Form</label><divclass="clear"></div></div></div></div><divclass="areaBody"><tableclass="formTable"><tbody><tr><tdcolspan="4"><spanclass="button"><span><ahref="javascript:sumbit();"class="btnSave">Submit</a></span></span></td></tr><tr><tdcolspan="4"> </td></tr><tr><tdalign="right">Parent Category Name:</td><tdcolspan="3"><form:inputpath="category.parent.name.fullName"readonly="true"id="parentCategory"cssClass="input readOnly"/></td></tr><tr><tdalign="right">Current Category Name:</td><td><form:inputpath="category.name.fullName"id="categoryName"cssClass="input"/></td><tdalign="right">description:</td><td><form:inputpath="category.description"id="description"cssClass="input"/></td></tr></tbody></table></div></form:form>2、实例2

spring mvc的表单类型转换(custom property editor)

9人收藏此文章,我要收藏发表于7个月前(2012-10-28 14:14) , 已有329次阅读，共1个评论spring mvc的表单类型转换太强大了，目前用到了两个简单的，一个是将表单中的file自动映射成byte[],这样文件上传（如果使用blob）就无需写任何代码了。另一个是将表单中的yyyy-MM-dd格式映射成java.util.Date，假设User.java中有如下这两种特殊的属性：

1	public class User implements Serializable{

2	private Datebirth;

3	private byte []icon;

4

}

注册这两种属性编辑器只需在Controller中定义如下这样一个

initBinder

方法:

01	@Controller ( "userController" )

02	@RequestMapping (value= "/user" )

03	public class UserController{

04	@RequestMapping (value= "create" ,method = RequestMethod.POST)

05	public Stringcreate( @ModelAttribute ( "user" )User user,

06	RedirectAttributesredirectAttributes) {

07	userService.createUser(user);

08	redirectAttributes.addFlashAttribute( "message" , "createsuccess!" );

09

10	return SUCCESS;

11

}

12

13	@InitBinder

14	protected void initBinder(

15	WebDataBinderbinder) throws ServletException{

16	binder.registerCustomEditor( byte []. class ,

17	new ByteArrayMultipartFileEditor());

18

19	SimpleDateFormatdateFormat = new SimpleDateFormat( "yyyy-MM-dd" );

20	dateFormat.setLenient( false );

21	binder.registerCustomEditor(Date. class , new CustomDateEditor(dateFormat, false ));

22

}

23

}

ByteArrayMultipartFileEditor和CustomDateEditor都是spring直接提供的。可以参考这两个类的源码,高级的自定义的还没用过，等用到的时候再补充到这里(2012-11-04补充）今天终于用到了自定义的Editor，我现在有一个User对象，它有一个Set<Role> roles集合。

1	public class User implements Serializable{

2	public Set<Role>roles = new HashSet<Role>();

Role有id和name属性，

1	public class Role implements Serializable{

2	private Longid; //

3	private Stringname; //

UserController如下

1	@RequestMapping (value= "create" ,method = RequestMethod.GET)

2	public StringcreateForm(ModelMap model) {

3	model.addAttribute( "roleList" ,roleService.findAllRoles());

4	Useruser = new User();

5	model.addAttribute(user);

6	return "user/user_new" ;

7

}

我的user_new.jsp如下：

1	< div class = "control-group" >

2	< label class = "control-label" for = "roles" >角色:</ label >

3	< div class = "controls" >

4	< sf:checkboxes path = "roles" items = "${roleList}" itemValue = "id" itemLabel = "name" />

5

</ div >

6

</ div >

用户在页面上check一个或多个角色，提交form，这时我们期望user对象中的roles集合能自动绑定用户选择的值，但是提交到服务器上的数据其实是一组roleId，我们需要在自定义的PropertyEditor中将其转成Role对象.可以像这样定义RoleEditor.java

01	public class RoleEditor extends PropertyEditorSupport{

02	private RoleServiceroleService;

03

04	public RoleEditor(RoleServiceroleService) {

05	this .roleService= roleService;

06

}

07

08

@Override

09	public void setAsText(Stringtext) throws IllegalArgumentException{

10	if (text!= null ){

11	Rolerole = roleService.findRoleById(Long.valueOf(text));

12	setValue(role);

13

} else {

14	setValue( null );

15

}

16

}

17

}

并在UserController中的initBinder方法中注册该编辑器

1	@InitBinder

2	protected void initBinder(

3	WebDataBinderbinder) throws ServletException{

4	//@see http://forum.springsource.org/showthread.php?59612-Service-injection-amp-PropertyEditor[/code]

5	binder.registerCustomEditor(Role. class , new RoleEditor(roleService));

6

}

这时在UserController的create方法中取得的User对象就是已经绑定了roles的了

1	@RequestMapping (value= "create" ,method = RequestMethod.POST)

2	public Stringcreate( @ModelAttribute ( "user" )User user,

3	RedirectAttributesredirectAttributes) {

4	userService.createUser(user);

5	redirectAttributes.addFlashAttribute( "message" , "createsuccess!" );

6

7	return SUCCESS;

8

}

值得注意的是，你必须要覆写Role的equals和hashCode方法，不然当你进入修改页面时，user的role属性不会自动的check上。RoleEditor可以简化成public class RoleEditor extends PropertyEditorSupport {@Overridepublic void setAsText(String text) throws IllegalArgumentException {if (text != null) {Role role = new Role();role.setId(Long.valueOf(text));setValue(role);} else {setValue(null);}}}保存时只用了id值，没有必要去数据库再查找一次