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85-002-11 在web项目中对Action层进行公共方法的抽取放入到BaseAction中

2016-06-29 12:28 435 查看

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11.1 在项目启动的时候，struts过滤器已经把jsp常用内置对象和map集合存入到了ActionContext和值栈（ValueStack）中。如果实现了XXXAware接口，就会从相应的ActionContext中获取对应的map进行传入（通过拦截器实现: servletConfig
这个拦截器是在struts-default.xml中配置的）
ServletConfigInterceptor.java

if(action instanceof RequestAware){
    ((RequestAware)action).setRequest((Map)context.get("request")) ;
}
if(action instanceof SessionAware){
    ((SessionAware)action).setSession(context.getSession()) ;
}
if(action instanceof ApplicationAware){
    ((ApplicationAware)action).setApplication(context.getApplication()) ;
}

11.2 CategoryAction.java中的Category赋值方式：显示层页面通过拦截器然后由OGNL表达式实现值的注入的下面进行具体步骤的分析。
在CategoryAction.java中定义一个语句，使其显示值栈中的栈顶内容或根节点内容

public String query(){
System.out.println(ActionContext.getContext().getValueStack().getRoot());
}

11.3 让CategoryAction实现数据模型驱动接口
CategoryAction.java

public class CategoryAction extends BaseAction implements ModelDriven{
public Object getModel() {
//它会把得到的值压入栈顶中（删除category对象的setter、getter方法）
        Category category = new Category() ;
        return category;
}

public String update(){
        System.out.println(ActionContext.getContext().getValueStack().getRoot());
        System.out.println("==update==") ;
        System.out.println(categoryService) ; //如果还没有与spring整合，所以输出为null
        System.out.println(category) ;
        //    categoryService.update(category);
        return "index" ;
    }

}

index.jsp

<a href="${pag
4000
eContext.request.contextPath}/category_update.action?id=1&type=儿童休闲&hot=false">ModelDriven驱动程序测试</a>

11.4 如果修改action
CategoryAction.java

private Integer id ;
    private Integer id1 ;
    public void setId1(Integer id1) {
        this.id1 = id1;
    }

public String update(){
        System.out.println(ActionContext.getContext().getValueStack().getRoot());
        System.out.println("==update==") ;
        System.out.println(category) ;
        System.out.println(id) ;
        System.out.println(id1) ;
        return "index" ;
    }

index.jsp

<a href="${pageContext.request.contextPath}/category_update.action?id=1&type=儿童休闲&hot=false&id1=123">ModelDriven驱动程序测试</a>

此时id=null, id1=123
11.5 ModelDriven 同样是通过拦截器（ModelDrivenInterceptor）实现的
ModelDrivenInterceptor.java

public String intercept(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();

if (action instanceof ModelDriven) {
ModelDriven modelDriven = (ModelDriven) action;
ValueStack stack = invocation.getStack();
Object model = modelDriven.getModel();
if (model != null) {
stack.push(model);
}

}
return invocation.invoke();
}

11.6 moderDriven是所有的action都可以使用的，所以可以把modelDriven放到baseAction中去同时要使用到泛型

public class BaseAction<T> extends ActionSupport implements RequestAware,SessionAware,ApplicationAware,ModelDriven<T> {

protected T model ;
public T getModel() {
ParameterizedType type = (ParameterizedType)this.getClass().getGenericSuperclass() ;
Class clazz = (Class)type.getActualTypeArguments()[0] ;
try {
model = (T)clazz.newInstance() ;
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return model;
}
}

然后在简化CategoryAction.java，这样就只剩下service层的类对象了。
CategoryAction.java

ublic class CategoryAction extends BaseAction<Category>{
private CategoryService categoryService ;
public void setCategoryService(CategoryService categoryService){
this.categoryService = categoryService ;
}
public String update(){
System.out.println(ActionContext.getContext().getValueStack().getRoot());
System.out.println("==update==") ;
System.out.println(model) ;
return "index" ;
}
public String save(){
System.out.println("==save==") ;
System.out.println(categoryService) ; //如果还没有与spring整合，所以输出为null
return "index" ;
}
public String query(){
System.out.println(ActionContext.getContext().getValueStack().getRoot());
request.put("categoryList", categoryService.query()) ;
session.put("categoryList", categoryService.query()) ;
application.put("categoryList", categoryService.query()) ;
return "index" ;
}
}

BaseAction.java

public class BaseAction<T> extends ActionSupport implements RequestAware,SessionAware,ApplicationAware,ModelDriven<T> {
protected Map<String,Object> request ;
protected Map<String,Object> session ;
protected Map<String,Object> application ;
//以下都是通过ActionContex传递过来的
public void setApplication(Map<String, Object> application) {
this.application = application ;
}
public void setSession(Map<String, Object> session) {
this.session = session ;
}
public void setRequest(Map<String, Object> request) {
this.request = request ;
}

protected T mode
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l ;
public T getModel() {
ParameterizedType type = (ParameterizedType)this.getClass().getGenericSuperclass() ;
Class clazz = (Class)type.getActualTypeArguments()[0] ;
try {
model = (T)clazz.newInstance() ;
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return model;
}
}public class BaseAction<T> extends ActionSupport implements RequestAware,SessionAware,ApplicationAware,ModelDriven<T> {
protected Map<String,Object> request ;
protected Map<String,Object> session ;
protected Map<String,Object> application ;
//以下都是通过ActionContex传递过来的
public void setApplication(Map<String, Object> application) {
this.application = application ;
}
public void setSession(Map<String, Object> session) {
this.session = session ;
}
public void setRequest(Map<String, Object> request) {
this.request = request ;
}

protected T model ;
public T getModel() {
ParameterizedType type = (ParameterizedType)this.getClass().getGenericSuperclass() ;
Class clazz = (Class)type.getActualTypeArguments()[0] ;
try {
model = (T)clazz.newInstance() ;
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return model;
}
}

11.7 为了进一步简化，现在连CategoryAction中的service也放到baseAction中去。

protected CategoryService categoryService ;
protected AccountService accountService;

public void setAccountService(AccountService accountService){
this.accountService = accountService ;
}
public void setCategoryService(CategoryService categoryService){
this.categoryService = categoryService ;
}

11.8 为了实现在baseAction中依赖spring注入，需要配置
applicationContext-action.xml

11.9 BaseAction定义好之后现在定义其他action实现类就变得简单了，下面定义
AccountAction.java

public class AccountAction extends BaseAction<Account>{
public String query(){
System.out.println(model);
return "index" ;
}
}

11.10 定义
index.jsp

<a href="account_query.action?id=10&login=zz">account</a>
 
${id } ${login } ${name} ${pass }

11.11 然后定义struts的配置文件
struts.xml

<action name="account_*" class="accountAction" method="{1}">
<result name="index">/index.jsp</result>
</action>

11.12 然后再定义spring的配置文件
applicationContext-action.xml

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