Task Flow使用指南之五：捕获异常

开发环境：JDevloper 11.1.2.2.0+ Oracle Database 10g Express Edition 10.2.0.1。

本实验接着上一个实验，由于使用Method Activity 绑定抛出异常的方法，ADF会在页面直接抛出异常，用户友好性较差，因此需要开发人员编写异常处理逻辑。
我将定义一个Task Flow Template，并在其中定义一个Exception Handler，然后让其它BTF继承该TaskFlow Template。

重要步骤说明:

1. 新建一个ADF TaskFlow Template：error-handler-task-flow
（1）拖放一个Method Activity，并Mark为Exception Handler。

（2）Method Activity指向Managed Bean中的方法：controllerExceptionHandler

public void controllerExceptionHandler() {
        System.out.println("######################## controllerExceptionHandler ");
        ControllerContext context = ControllerContext.getInstance();
        ViewPortContext currentRootViewPort = context.getCurrentRootViewPort();
        Exception exceptionData = currentRootViewPort.getExceptionData();

        if (currentRootViewPort.isExceptionPresent()) {
            exceptionData.printStackTrace();
            currentRootViewPort.clearException();

            FacesContext facesContext = FacesContext.getCurrentInstance();
            facesContext.addMessage(null,
                                    new FacesMessage(FacesMessage.SEVERITY_ERROR, exceptionData.getMessage(), null));
        }
    }

2. 让employees-taskflow-btf继承ADF TaskFlow Template：error-handler-task-flow


3. 运行，点击Go to ProcessData Method按钮
这次页面上不再直接抛出异常，而是会调用controllerExceptionHandler，该方法使用弹出窗口显示异常:

同时，在Console日志中输出如下：
######################## controllerExceptionHandler 
oracle.jbo.JboException: JboException! Data Processing Failed
at model.AppModuleImpl.processData(AppModuleImpl.java:98)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at oracle.adf.model.binding.DCInvokeMethod.invokeMethod(DCInvokeMethod.java:655)
at oracle.adf.model.binding.DCDataControl.invokeMethod(DCDataControl.java:2162)
at oracle.adf.model.bc4j.DCJboDataControl.invokeMethod(DCJboDataControl.java:3088)
at oracle.adf.model.binding.DCInvokeMethod.callMethod(DCInvokeMethod.java:266)
at oracle.jbo.uicli.binding.JUCtrlActionBinding.doIt(JUCtrlActionBinding.java:1626)
at oracle.adf.model.binding.DCDataControl.invokeOperation(DCDataControl.java:2169)
at oracle.jbo.uicli.binding.JUCtrlActionBinding.invoke(JUCtrlActionBinding.java:731)
at oracle.adf.controller.v2.lifecycle.PageLifecycleImpl.executeEvent(PageLifecycleImpl.java:402)
at oracle.adfinternal.view.faces.model.binding.FacesCtrlActionBinding._execute(FacesCtrlActionBinding.java:252)
at oracle.adfinternal.view.faces.model.binding.FacesCtrlActionBinding.execute(FacesCtrlActionBinding.java:210)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(Unknown Source)
at com.sun.el.MethodExpressionImpl.invoke(Unknown Source)
 

Project 下载：ADF_TaskFlow_PageToTaskFlow(ExceptionHandler2).7z