在 Grails 3.0.9 中向 src/groovy 注入服务

Question

我正在尝试创建端点文件。所以我创建了一个名为 ServerEndPointDemo.groovy

的文件

package com.akiong

import grails.util.Environment
import grails.util.Holders

import javax.servlet.ServletContext
import javax.servlet.ServletContextEvent
import javax.servlet.ServletContextListener
import javax.servlet.annotation.WebListener
import javax.websocket.EndpointConfig
import javax.websocket.OnClose
import javax.websocket.OnError
import javax.websocket.OnMessage
import javax.websocket.OnOpen
import javax.websocket.Session
import javax.websocket.server.PathParam
import javax.websocket.server.ServerContainer
import javax.websocket.server.ServerEndpoint
import javax.websocket.EncodeException

import javax.servlet.annotation.WebListener
import java.util.concurrent.CopyOnWriteArraySet

@WebListener
@ServerEndpoint(value="/chat/test/{username}")

public class ServerEndPointDemo implements ServletContextListener {
    private static HashMap<String, String> usersMap = new HashMap<String, String>();
    private static final Set<ServerEndPointDemo> connections = new CopyOnWriteArraySet<>();
    private String username
    private Session session

    @OnOpen
    public void  handleOpen(Session session,@PathParam("username") String user){
        System.out.println("-------------------------------------");

        System.out.println(session.getId() + " has opened a connection");
        println "user = "+user

        connections.add(this);
        this.username   = user
        this.session    = session

        addUserToMap(username,session.getId())

        try{
            def ctx = Holders.applicationContext
            chatService = ctx.chatService
        }
        catch (Exception e){
            println "e = "+e
        }

    }

    @OnClose
    public void  handleClose(Session session){  
        System.out.println("Session " +session.getId()+" has ended");  
    }

    @OnMessage
    public String handleMessage(String message,Session session){
        chatService.saveSessionAdminJava(session.getId())    
    }

    @OnError
    public void  handleError(Throwable t){
        println "error ~"
    }  

    private void sendMessageToAll(String message){
        println "session.size() = "+sessions.size()
        for(Session s : sessions){
            try {
                s.getBasicRemote().sendText(message);
                println "sent to session = "+s.getId()
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}
`

我尝试使用此代码从服务调用方法：

try {
    def ctx = Holders.applicationContext
    chatService = ctx.chatService
} catch (Exception e) {
    println "e = " + e
}

这是我的服务：

package com.akiong.services

import com.akiong.maintenance.Chat

class ChatService {

    def serviceMethod() {

    }

    def saveSessionAdminJava(def sessionJava) {
        println "jaln!!!"
        def chatInstance = Chat.findByIsAdmin("1")
        chatInstance.sessionJava = sessionJava
        chatInstance.save(failOnError: true)
    }
}

但是在我尝试运行这段代码后，我收到了这个错误：

Error : groovy.lang.MissingPropertyException: No such property: chatService for
class: com.akiong.ServerEndPointDemo

有人知道如何在 src/groovy 中从服务调用方法到文件吗？

Answer 1

import org.apache.commons.logging.LogFactory;
import org.codehaus.groovy.grails.commons.ApplicationHolder as AH

class MyClass{
    private static final log = LogFactory.getLog(this)
    def ctx = AH.application.mainContext
    def authService=ctx.authService

    def method(){
        log.debug "into MyClass method"
    }
}

Answer 2

所以问题来了。您编写的代码对于注入服务是正确的：

try {
    def ctx = Holders.applicationContext
    chatService = ctx.chatService
} catch (Exception e) {
    println "e = "+e
}

但是 chatService 没有在您的 class 中的任何地方定义。因此，即使您的 handleOpen 方法被调用，也必须抛出 MissingPropertyException 但由于您已经处理了顶层 Exception class （ 永远不应该鼓励) handleOpen 方法中的异常被抑制了。

现在，稍后在您的 handleMessage 方法中，同样的问题再次发生 chatService 未定义，因此您得到了您在问题中发布的异常。

所以，您现在知道答案了 :-) 只需在 ServerEndPointDemo class.

中定义 chatService

更新：

public class ServerEndPointDemo implements ServletContextListener {
    private static HashMap<String, String> usersMap = new HashMap<String, String>();
    private static final Set<ServerEndPointDemo> connections = new CopyOnWriteArraySet<>();
    private String username
    private Session session

    def chartService    // Initialize here
    // rest of your code
}

在 Grails 3.0.9 中向 src/groovy 注入服务

Inject services to src/groovy in Grails 3.0.9

grails

groovy

grails-3.0.9