根据从超链接发送给它的参数,有人能告诉我一个代码有效的方法让spring mvc中的对象属性发生变化吗?
我正在修改spring petclinic示例应用程序,以便“所有者”详细信息页面可以显示特定“所有者”拥有的每种“宠物”的单独列表。目前,“宠物”列表是每个“所有者”的属性,并且可以在jstl中作为owner.pets访问。我想要的是我的jstl代码能够从jstl调用owner.cats,owner.dogs,owner.lizards等,并在网页的不同部分填充几个单独的列表,即使所有的猫,狗和蜥蜴存储在同一个基础数据表中。
我如何做到这一点?
以下是JpaOwnerRepositoryImpl.java的相关方法:
@SuppressWarnings("unchecked")
public Collection<Owner> findByLastName(String lastName) {
// using 'join fetch' because a single query should load both owners and pets
// using 'left join fetch' because it might happen that an owner does not have pets yet
Query query = this.em.createQuery("SELECT DISTINCT owner FROM Owner owner left join fetch owner.pets WHERE owner.lastName LIKE :lastName");
query.setParameter("lastName", lastName + "%");
return query.getResultList();
}
@Override
public Owner findById(int id) {
// using 'join fetch' because a single query should load both owners and pets
// using 'left join fetch' because it might happen that an owner does not have pets yet
Query query = this.em.createQuery("SELECT owner FROM Owner owner left join fetch owner.pets WHERE owner.id =:id");
query.setParameter("id", id);
return (Owner) query.getSingleResult();
}
以下是Owner.java的相关方面:
@OneToMany(cascade = CascadeType.ALL, mappedBy = "owner")
private Set<Pet> pets;
protected Set<Pet> getPetsInternal() {
if (this.pets == null) {this.pets = new HashSet<Pet>();}
return this.pets;
}
public List<Pet> getPets() {
List<Pet> sortedPets = new ArrayList<Pet>(getPetsInternal());
PropertyComparator.sort(sortedPets, new MutableSortDefinition("name", true, true));
return Collections.unmodifiableList(sortedPets);
}
这是OwnerController.java的一部分,它管理网址模式“/所有者”,我希望我的jstl能够在页面的不同部分单独列出猫,狗,蜥蜴等(不是在一个分组中)列表,但在几个单独的列表中。):
@RequestMapping(value = "/owners", method = RequestMethod.GET)
public String processFindForm(@RequestParam("ownerID") String ownerId, Owner owner, BindingResult result, Map<String, Object> model) {
Collection<Owner> results = this.clinicService.findOwnerByLastName("");
model.put("selections", results);
int ownrId = Integer.parseInt(ownerId);
model.put("sel_owner",this.clinicService.findOwnerById(ownrId));
return "owners/ownersList";
}
答案 0 :(得分:1)
既然你要求一个非冗长的解决方案,你可以做这种半脏的修复。
@Transient
private Set<Pet> cats = new HashSet<Pet>();
[...]
// Call this from OwnerController before returning data to page.
public void parsePets() {
for (Pet pet : getPetsInternal()) {
if ("cat".equals(pet.getType().getName())) {
cats.add(pet);
}
}
}
public getCats() {
return cats;
}
[...]
<h3>Cats</h3>
<c:forEach var="cat" items="${owner.cats}">
<p>Name: <c:out value="${cat.name}" /></p>
</c:forEach>
<h3>All pets</h3>
[...]
/**
* Custom handler for displaying an owner.
*
* @param ownerId the ID of the owner to display
* @return a ModelMap with the model attributes for the view
*/
@RequestMapping("/owners/{ownerId}")
public ModelAndView showOwner(@PathVariable("ownerId") int ownerId) {
ModelAndView mav = new ModelAndView("owners/ownerDetails");
Owner owner = this.clinicService.findOwnerById(ownerId);
owner.parsePets();
mav.addObject(owner);
return mav;
}