Delegate is not set yet

部署错误：
Delegate is not set yet
有关详细信息，请参见服务器日志。
        at org.netbeans.modules.j2ee.deployment.devmodules.api.Deployment.deploy(Deployment.java:205)
        at org.netbeans.modules.j2ee.ant.Deploy.execute(Deploy.java:103)
        at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
        at sun.reflect.GeneratedMethodAccessor180.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
        at org.apache.tools.ant.Task.perform(Task.java:348)
        at org.apache.tools.ant.Target.execute(Target.java:357)
        at org.apache.tools.ant.Target.performTasks(Target.java:385)
        at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
        at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
        at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
        at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
        at org.apache.tools.ant.module.bridge.impl.BridgeImpl.run(BridgeImpl.java:278)
        at org.apache.tools.ant.module.run.TargetExecutor.run(TargetExecutor.java:498)
        at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:151)
Caused by: java.lang.IllegalStateException: Delegate is not set yet
        at org.netbeans.modules.j2ee.deployment.impl.TargetModule.delegate(TargetModule.java:180)
        at org.netbeans.modules.j2ee.deployment.impl.TargetModule.getTarget(TargetModule.java:194)
        at org.netbeans.modules.j2ee.deployment.impl.TargetServer.canFileDeploy(TargetServer.java:222)
        at org.netbeans.modules.j2ee.deployment.impl.TargetServer.supportsDeployOnSave(TargetServer.java:730)
        at org.netbeans.modules.j2ee.deployment.devmodules.api.Deployment.deploy(Deployment.java:174)
        ... 16 more
生成失败（总时间：0 秒）

原因:This is because your netbeans is using the wrong version of Ant.

You need to ensure you have Ant 1.7.1 installed,  and that it is the
default binary that is run when you start netbeans.