Java 了解EJB中无状态企业会话bean的功能
我是EJB新手。我试图理解无状态企业bean的功能 请看以下示例:Java 了解EJB中无状态企业会话bean的功能,java,servlets,jakarta-ee,ejb,stateless-session-bean,Java,Servlets,Jakarta Ee,Ejb,Stateless Session Bean,我是EJB新手。我试图理解无状态企业bean的功能 请看以下示例: @Stateless @LocalBean public class FlightService implements Serializable { /** * Default constructor. */ public FlightService() { // TODO Auto-generated constructor stub } /** * @return the id */ public
@Stateless
@LocalBean
public class FlightService implements Serializable {
/**
* Default constructor.
*/
public FlightService() {
// TODO Auto-generated constructor stub
}
/**
* @return the id
*/
public Integer getId() {
return id;
}
/**
* @param id the id to set
*/
public void setId(Integer id) {
this.id = id;
}
/**
* @return the from
*/
public String getFrom() {
return from;
}
/**
* @param from the from to set
*/
public void setFrom(String from) {
this.from = from;
}
/**
* @return the to
*/
public String getTo() {
return to;
}
public void setTo(String to) {
this.to = to;
}
/**
* @return the price
*/
public Integer getPrice() {
return price;
}
/**
* @param price the price to set
*/
public void setPrice(Integer price) {
this.price = price;
}
/**
* @return the numOfSeats
*/
public Integer getNumOfSeats() {
return numOfSeats;
}
/**
* @param numOfSeats the numOfSeats to set
*/
public void setNumOfSeats(Integer numOfSeats) {
this.numOfSeats = numOfSeats;
}
/**
* @return the airplaneModel
*/
public String getAirplaneModel() {
return airplaneModel;
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return "FlightService [id=" + id + ", from=" + from + ", to=" + to + ", price=" + price + ", numOfSeats="
+ numOfSeats + ", airplaneModel=" + airplaneModel + "]";
}
/**
* @param airplaneModel the airplaneModel to set
*/
public void setAirplaneModel(String airplaneModel) {
this.airplaneModel = airplaneModel;
}
private Integer id =23467;
private String from="Los Angles";
private String to="London";
private Integer price=400;
private Integer numOfSeats=250;
private String airplaneModel="Boeing 787";
}
下面是使用@EJB依赖项注入的类
@EJB
private FlightService flightService;
@EJB
private FlightService flightService1;
@EJB
private FlightService flightService2;
@EJB
private FlightService flightService3;
@EJB
private FlightService flightService4;
@EJB
private FlightService flightService5;
@EJB
private FlightService flightService6;
public FlightDetails() {
super();
System.out.println(flightService);
}
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter out = response.getWriter();
response.setContentType("text/html");
flightService.setAirplaneModel("Rishanth");
flightService.setFrom("vijaywada");
flightService.setId(1);
flightService.setNumOfSeats(4);
flightService.setPrice(4);
flightService.setTo("hyderabad");
flightService4.setAirplaneModel("cannadian Airlines");
out.println(flightService.getAirplaneModel());
}
我想在打印时理解
"flightService.getAirplaneModel()"
为什么要设置该值
"flightService4.setAirplaneModel("cannadian Airlines");"
任何帮助都将不胜感激。这主要是因为J2EE服务器将为每个@Statelss EJB提供一个池,并且将为每个客户端创建一个新实例。在您的情况下,只有一个客户机正在使用注入的EJB 参考:
类似的问题:这主要是因为J2EE服务器将为每个@Statelss EJB创建一个池,并且将为每个客户端创建一个新实例。在您的情况下,只有一个客户机正在使用注入的EJB 参考:
类似的问题:因为bean应该是无状态的,即它没有任何会话状态。顺便说一句,即使它有一个,你也在flightService4上调用setAirplaneModel,在flightService上调用getAirplaneModel。@jbnize我为这个错误道歉。请再次讨论这个问题。同样,bean应该是无状态的。所以它不能有任何对话状态。容器可以自由地为任何请求重用任何实例,前提是同一实例不会同时处理两个请求。因为bean应该是无状态的,即它没有任何会话状态。顺便说一句,即使它有一个,你也在flightService4上调用setAirplaneModel,在flightService上调用getAirplaneModel。@jbnize我为这个错误道歉。请再次讨论这个问题。同样,bean应该是无状态的。所以它不能有任何对话状态。容器可以自由地为任何请求重用任何实例,前提是同一实例不会同时处理两个请求。