Servlet的API的访问:(三种方式)

Servlet的API的访问:(三种方式)----也就是获取参数的三种方式.

1 .完全解耦合的方式:(ActionContext)

ActionContext的方法:

* Map<String,Object> getParameters(); ---接收参数.

* put(String key,Object value); ---向request域中存数据.

* Map<String,Object> getSession(); ---获得session的Map.

* Map<String,Object> getApplication(); ---获得application的Map.

代码:

// 1.接收表单的数据:
ActionContext actionContext = ActionContext.getContext();
Map<String,Object> map = actionContext.getParameters();
String[] names = (String[]) map.get( "name" );
System.out.println(names[ 0 ]);
String[] sexs = (String[]) map.get( "sex" );
System.out.println(sexs[ 0 ]);
// 2.向域中存数据:
// 2.1向request域中存值:
actionContext.put( "reqName" , "美美" );
// 2.2向session域中存值:
actionContext.getSession().put( "sessName" , "标哥" );
// 2.3向application域中存值:
actionContext.getApplication().put( "appName" , "大标哥" );

2 .使用接口注入的方式:

实现接口的方式:

* ServletRequestAware:

* ServletContextAware:

* ServletResponseAware:

代码:

public class RequestAction2 extends ActionSupport implements ServletRequestAware,ServletContextAware{
private HttpServletRequest request;
private ServletContext context;
@Override
public String execute() throws Exception {
// 接收参数:
String name = request.getParameter( "name" );
String sex = request.getParameter( "sex" );
System.out.println(name);
System.out.println(sex);
// 向域中保存数据:
request.setAttribute( "reqName" , "凤姐" );
request.getSession().setAttribute( "sessName" , "杜宏" );
context.setAttribute( "appName" , "芙蓉" );
return SUCCESS;
}
@Override
public void setServletRequest(HttpServletRequest request) {
this .request = request;
}
@Override
public void setServletContext(ServletContext context) {
this .context  = context;
}
}

3 .使用类中静态方法的方式:(耦合)

ServletActionContext:

* getRequest();

* getServletContext();

* getResponse();

代码:

@Override
public String execute() throws Exception {
// 接收参数:
HttpServletRequest req = ServletActionContext.getRequest();
String name  = req.getParameter( "name" );
String sex  = req.getParameter( "sex" );
System.out.println(name);
System.out.println(sex);
// 向域中保存数据:
req.setAttribute( "reqName" , "天一" );
req.getSession().setAttribute( "sessName" , "冠希" );
ServletActionContext.getServletContext().setAttribute( "appName" , "冰冰" );
return super .execute();
}

4 .比较三种方式:

最好:第一种完全解耦合方式.

最熟练:第三种方式.

来自为知笔记(Wiz)