我想用 servlet 打开一个文件
我有一个返回这种类型 byte[] 的函数
我有一个包含按钮的 jps 文件，当我单击此按钮时，将调用此方法（咨询）我尝试此代码
public class Test{
private HttpServletRequest request;
private HttpServletResponse response;
public void consult() {
P8Connector connector = new P8Connector(TypeEnum.CE.value(),
"test");
GetDocumentsListInFolder getDocumentsListInFolder = new GetDocumentsListInFolder();
List<Document> list = new ArrayList<Document>();
list = getDocumentsListInFolder.execute(connector,
"/test", "1");
for (int i = 0; i < list.size(); i++) {
Document doc = (Document)list.get(i);
GetDocumentContent c = new GetDocumentContent();
byte[] is = c.execute(connector , doc);
response.setHeader("Expires", "0");
response.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
response.setHeader("Pragma", "public");
response.setContentType("application/pdf");
InputStream in = new FileInputStream("20130114.008.01.pdf");
OutputStream out = response.getOutputStream();
// Copy the bits from instream to outstream
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
in.close();
}
public void setServletRequest(HttpServletRequest request){
this.request = request;
}
public HttpServletRequest getServletRequest(){
return request;
}
public void setServletResponse(HttpServletResponse response){
this.response = response;
}
public HttpServletResponse getServletResponse(){
return response;
}
}
但是当我运行这段代码时，我有
这个错误：空点异常
在这一行
response.setHeader("Expires", "0");