参数化对象属性

有人能告诉我一个代码有效的方法来在spring mvc中根据从超链接发送给它的参数更改对象属性吗？

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。

我该如何做到这一点？

以下是JpaOwnerRepositoryImpl.java的相关方法：

@SuppressWarnings("unchecked") public Collection 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 pets; protected Set getPetsInternal() { if (this.pets == null) {this.pets = new HashSet();} return this.pets; } public List getPets() { List sortedPets = new ArrayList(getPetsInternal()); PropertyComparator.sort(sortedPets, new MutableSortDefinition("name", true, true)); return Collections.unmodifiableList(sortedPets); } 

这是OwnerController.java的一部分，它管理url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（不是在一个分组列表中，但是在几个单独的名单中。）：

 @RequestMapping(value = "/owners", method = RequestMethod.GET) public String processFindForm(@RequestParam("ownerID") String ownerId, Owner owner, BindingResult result, Map model) { Collection results = this.clinicService.findOwnerByLastName(""); model.put("selections", results); int ownrId = Integer.parseInt(ownerId); model.put("sel_owner",this.clinicService.findOwnerById(ownrId)); return "owners/ownersList"; } 

Answer 1

既然你要求一个非详细的解决方案，你可以做这种半脏修复。

Owner.java

 @Transient private Set cats = new HashSet(); 

[…]

 // 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; } 

ownerDetail.jsp

 [...] 
Cats
  
Name: 
  
All pets
 [...] 

OwnerController.java

 /** * 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; }