java - Websphere 中的 NullPointerException 异常？

Question

我使用PrintWriter对另一个servlet进行servlet调用。无法重定向特定目标URL。我的代码是

PrintWriter pw= null;
pw= response.getWriter();
pw.print("URL TO Redirect");
pw.close();

Websphere 系统错误日志:

java.lang.NullPointerException
    at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:485)
    at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:301)
    at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:275)
    at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214)
    at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113)
    at com.ibm.ws.tcp.channel.impl.WorkQueueManager.requestComplete(WorkQueueManager.java:557)
        at com.ibm.ws.tcp.channel.impl.WorkQueueManager.attemptIO(WorkQueueManager.java:607)
    at com.ibm.ws.tcp.channel.impl.WorkQueueManager.workerRun(WorkQueueManager.java:984)
    at com.ibm.ws.tcp.channel.impl.WorkQueueManager$Worker.run(WorkQueueManager.java:1069)
    at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1563)

Answer 1

pw.close; 应该是 pw.close();。

否则您将尝试访问名为 close 的非私有(private)字段。如果存在的话，它可能是null。

除此之外，您的代码看起来不错，NPE 原因在其他地方。