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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 }
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原文地址：http://www.cnblogs.com/cnjavahome/p/4227567.html
