request.getReader()方法为什么调用一次以后就再也不能取出数据呢？

Philip1314 2003-08-16 03:25:33

在同一个JSP页面中
java.io.BufferedReader rd = request.getReader();
String str;
while ( (str=rd.readLine())!=null) {
System.out.println(str);
}

//第二次
rd = request.getReader();
while ( (str=rd.readLine())!=null) {
System.out.println(str);
}

为什么第二次就打印不出任何数据呢？

...全文

1877 3 打赏收藏转发到动态举报

写回复

用AI写文章

3 条回复

切换为时间正序

请发表友善的回复…

发表回复

one_bird 2003-08-16

打赏
举报

学习~!

whodsow 2003-08-16

打赏
举报

ServletRequest的getReader()方法及其getInputStream()方法均只能被调用一次，而且前者与后者也是冲突的，调用了前者就不能再调用后者，如Servlet的document:
--------------------------------------------------------------------------------

getInputStream
public ServletInputStream getInputStream()
throws java.io.IOExceptionRetrieves the body of the request as binary data using a ServletInputStream. Either this method or getReader() may be called to read the body, not both.
Returns:
a ServletInputStream object containing the body of the request
Throws:
java.lang.IllegalStateException - if the getReader() method has already been called for this request
java.io.IOException - if an input or output exception occurred

--------------------------------------------------------------------------------

getReader
public java.io.BufferedReader getReader()
throws java.io.IOExceptionRetrieves the body of the request as character data using a BufferedReader. The reader translates the character data according to the character encoding used on the body. Either this method or getInputStream() may be called to read the body, not both.
Returns:
a BufferedReader containing the body of the request
Throws:
java.io.UnsupportedEncodingException - if the character set encoding used is not supported and the text cannot be decoded
java.lang.IllegalStateException - if getInputStream() method has been called on this request
java.io.IOException - if an input or output exception occurred
See Also:
getInputStream()

Shield Pai 2003-08-16