Spring的MVC模块
Spring提供了自己的MVC框架实现，相比Struts、WebWork等MVC模块，Spring的MVC模块显得小巧而灵活。Spring的MVC使用Controller处理用户请求，此处的Controller类似于Struts1.x中的Action。SpringMVC作为Spring框架的一部分，在进行框架整合时不需要像Struts1&2那样特意的去融合到Spring里面，其本身就在Spring里面。
先定义如下各层：
域模型层实体类Cat：
1 package com.spring.mvc;
2
3 import java.util.Date;
4
5 import javax.persistence.Entity;
6 import javax.persistence.GeneratedValue;
7 import javax.persistence.GenerationType;
8 import javax.persistence.Id;
9 import javax.persistence.Table;
10 import javax.persistence.Temporal;
11 import javax.persistence.TemporalType;
12
13 @Entity
14 @Table(name = "tb_cat")
15 public class Cat {
16
17 @Id
18 @GeneratedValue(strategy = GenerationType.AUTO)
19 private Integer id;
20 private String name;
21 @Temporal(value = TemporalType.TIMESTAMP)
22 private Date createdDate;
23 public Date getCreatedDate() {
24 return createdDate;
25 }
26
27 public void setCreatedDate(Date createdDate) {
28 this.createdDate = createdDate;
29 }
30
31 public Integer getId() {
32 return id;
33 }
34
35 public void setId(Integer id) {
36 this.id = id;
37 }
38
39 public String getName() {
40 return name;
41 }
42
43 public void setName(String name) {
44 this.name = name;
45 }
46 }
业务逻辑层接口ICatService：
1 package com.spring.mvc;
2
3 import java.util.List;
4
5 public interface ICatService {
6 public void createCat(Cat cat);
7 public List<Cat> listCats();
8 public int getCatsCount();
9 }
业务逻辑层接口的实现类CatServiceImpl：
1 package com.spring.mvc;
2
3 import java.util.List;
4
5 public class CatServiceImpl implements ICatService {
6 private ICatDao catDao;
7 public ICatDao getCatDao() {
8 return catDao;
9 }
10
11 public void setCatDao(ICatDao catDao) {
12 this.catDao = catDao;
13 }
14
15 public void createCat(Cat cat) {
16 if (catDao.findCatByName(cat.getName()) != null){
17 throw new RuntimeException("猫" + cat.getName() + "已经存在。" );
18 }
19 catDao.createCat(cat);
20 }
21
22 public int getCatsCount() {
23 return catDao.getCatsCount();
24 }
25
26 public List<Cat> listCats() {
27 return catDao.listCats();
28 }
29 }
数据库持久层接口ICatDao：
1 package com.spring.mvc;
2
3 import java.util.List;
4
5 public interface ICatDao {
6 public void createCat(Cat cat);
7 public Cat findCatByName(String name);
8 public List<Cat> listCats();
9 public int getCatsCount();
10 }
数据库持久层实现类CatDaoImpl：
1 package com.spring.mvc;
2
3 import java.util.List;
4
5 import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
6
7 public class CatDaoImpl extends HibernateDaoSupport implements ICatDao {
8
9 public void createCat(Cat cat) {
10 this.getHibernateTemplate().persist(cat);
11 }
12
13 public Cat findCatByName(String name) {
14 List<Cat> catList = this.getHibernateTemplate().find(" select c from Cat c where c.name = ? ", name);
15 if (catList.size() > 0)
16 return catList.get(0);
17 return null;
18 }
19
20 public int getCatsCount() {
21 return (Integer) this.getSession(true).createQuery(" select count(c) from Cat c ").uniqueResult();
22 }
23
24 public List<Cat> listCats() {
25 return this.getHibernateTemplate().find(" select c from Cat c ");
26 }
27 }
SpringMVC的控制层和视图层
SpringMVC的控制层是Controller。Controller是个接口，一般直接继承AbstractController抽象类，并实现handleRequestInternal方法，此方法类似于Struts1.x中的execute()方法。
SpringMVC的视图层使用的是ModelAndView对象。handleRequestInternal方法返回的即时此对象，ModelAndView相当于Struts1.x中的ActionForward。
ModelAndView可以方便的传递参数，例如
return new ModelAndView("cal/listCat","cat",cat);
等价于
request.setAttribute("cat",cat);
return new ModelAndView("cal/listCat");
当传递多个参数时，可以使用Map，例如：
Map map = new HashMap();
map.put("cat",cat);
map.put("catList",catList);
return new ModelAndView("cat/listCat",map);
1 package com.spring.mvc;
2
3 import java.util.Date;
4 import java.util.List;
5
6 import javax.servlet.http.HttpServletRequest;
7 import javax.servlet.http.HttpServletResponse;
8
9 import org.springframework.web.servlet.ModelAndView;
10 import org.springframework.web.servlet.mvc.AbstractController;
11
12 public class CatController extends AbstractController {
13
14 private ICatService catService;
15
16 @Override
17 protected ModelAndView handleRequestInternal(HttpServletRequest request,HttpServletResponse response) throws Exception {
18 String action = request.getParameter("action");
19 if ("add".equals(action)) {
20 return this.add(request, response);
21 }
22 return this.list(request, response);
23 }
24
25 protected ModelAndView list(HttpServletRequest request,HttpServletResponse response) throws Exception {
26 List<Cat> catList = catService.listCats();
27 request.setAttribute("catList", catList);
28 return new ModelAndView("cat/listCat");
29 }
30
31 protected ModelAndView add(HttpServletRequest request,HttpServletResponse response) throws Exception {
32 Cat cat = new Cat();
33 cat.setName(request.getParameter("name"));
34 cat.setCreatedDate(new Date());
35 catService.createCat(cat);
36 return new ModelAndView("cat/listCat", "cat", cat);
37 }
38
39 public ICatService getCatService() {
40 return catService;
41 }
42
43 public void setCatService(ICatService catService) {
44 this.catService = catService;
45 }
46 }
多业务分发器
如果一个Controller需要处理多种业务逻辑，可以使用MultiActionController。MultiActionController就是一个分发器，相当于Struts1.x中的DispatchAction分发器，能根据某参数值将不同的请求分发到不同的方法上，比如可以设置分发器参数为method，则URL地址访问catMulti.mvc?method=add时将会执行add方法。CatMultiController不需要继承父类的任何方法，只需要定义形如public ModelAndView xxx(HttpServletRequest request,HttpServletResponse response)的方法，当地址栏参数method为xxx时，Spring会通过反射调用xxx()方法。
1 package com.spring.mvc;
2
3 import java.util.Date;
4 import java.util.List;
5
6 import javax.servlet.http.HttpServletRequest;
7 import javax.servlet.http.HttpServletResponse;
8
9 import org.springframework.web.servlet.ModelAndView;
10 import org.springframework.web.servlet.mvc.multiaction.MultiActionController;
11
12 public class CatMultiController extends MultiActionController {
13
14 private ICatService catService;
15
16 public ICatService getCatService() {
17 return catService;
18 }
19
20 public void setCatService(ICatService catService) {
21 this.catService = catService;
22 }
23
24 @SuppressWarnings("unchecked")
25 public ModelAndView add(HttpServletRequest request,HttpServletResponse response) {
26 Cat cat = new Cat();
27 cat.setName(request.getParameter("name"));
28 cat.setCreatedDate(new Date());
29 catService.createCat(cat);
30 return this.list(request, response);
31 }
32
33 @SuppressWarnings("unchecked")
34 public ModelAndView list(HttpServletRequest request,HttpServletResponse response) {
35 List<Cat> catList = catService.listCats();
36 request.setAttribute("catList", catList);
37 return new ModelAndView("cat/listCat");
38 }
39
40 }
时间： 2024-11-02 14:24:39