查看Servlet的API发现问题：
public java.io.PrintWriter getWriter()
throws java.io.IOException
Returns a PrintWriter object that can send character text to the client. The PrintWriter uses the character encoding returned by getCharacterEncoding(). If the response's character encoding has not been specified as described in getCharacterEncoding (i.e., the method just returns the default value ISO-8859-1), getWriter updates it to ISO-8859-1.
Calling flush() on the PrintWriter commits the response.
Either this method or getOutputStream() may be called to write the body, not both.
Returns:
a PrintWriter object that can return character data to the client
Throws:
UnsupportedEncodingException - if the character encoding returned by getCharacterEncoding cannot be used
java.lang.IllegalStateException - if the getOutputStream method has already been called for this response objectjava.io.IOException - if an input or output exception occurred
See Also:
getOutputStream(), setCharacterEncoding(java.lang.String)
如API所言，由于ServletResponse.getOutputStream()方法和该方法都有可能被调用，来输出JSP页面的内容，如果其中的一个方法被调用了，再调用另一个方法就会抛出异常。
解决方案：
加入如下代码：
out.clear();
out = pageContext.pushBody();
代码作用：
out.clear()：清空缓存的内容。
pageContext.pushBody()：参考API
public BodyContent pushBody()Return a new BodyContent object, save the current "out" JspWriter, and update the value of the "out" attribute in the page scope attribute namespace of the PageContext.
Returns:
the new BodyContent
·返回一个新的BodyContent(代表一个HTML页面的BODY部分内容）
·保存JspWriter实例的对象out
·更新PageContext的out属性的内容
分享到：
相关推荐
NULL 博文链接：https://javal.iteye.com/blog/1993903
1.在tomcat6.0下jsp出现getOutputStream() has already been called for this response异常的原因和解决方法 在tomcat6.0下jsp中出现此错误一般都是在jsp中使用了输出流（如输出图片验证码，文件下载等），没有...
纠结了半天的 java.lang.IllegalStateException: getOutputStream() has already。这个问题困扰了半天,在网上查阅了大量资料 出这个错误一般就是下面2个.....
验证码出现getOutputStream() has already been called for this response错误解决
解决了getOutputStream() has already been called for this response. 并将产生验证码的逻辑从JSP页面中分离出来，单独写了一个类 便于重用。
NULL 博文链接：https://nethub2.iteye.com/blog/2023937
servlet的response可以对返回的内容和格式进行一些设置。
Returns a boolean indicating whether the named response header has already been set. contextDestroyed(ServletContextEvent) - Method in interface javax.servlet.ServletContextListener Notification ...
* This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server ...
OutputStream o = response.getOutputStream(); // 将图片转换成字符串 File f = new File("f:\\Vista.png"); FileInputStream fis = new FileInputStream( f ); byte[] bytes = new byte[fis.available...
heads是excel表头,datalist是数据public void createExcelStream(HttpServletResponse response,String filename,String[] heads,List[]> datalist){ try{ OutputStream os = response.getOutputStream();...
IOUtils.copy(inputStream, response.getOutputStream()); response.flushBuffer(); System.out.println("输出成功！"); } HTML前端接response收流： <source src="http://localhost:8081/file/output...
随机获取验证码 public class CheckNumberServlet extends HttpServlet { ... ServletOutputStream sos = response.getOutputStream();…………………………………………………………………………………………
public void code(HttpServletRequest request, HttpServletResponse response) throws IOException{ String[] tableNames = new String[]{};... IOUtils.write(data, response.getOutputStream()); }
OutputStream outs = response.getOutputStream();// 获取文件输出IO流 BufferedOutputStream bouts = new BufferedOutputStream(outs); response.setContentType("application/x-download");// 设置response...
ServletOutputStream responseOutputStream = response.getOutputStream(); ImageIO.write(bufferImage, "JPEG", responseOutputStream); responseOutputStream.flush(); responseOutputStream.close(); } } ...
import java.io.*; import java.util.*; import javax.servlet.*; ... public class MyServlet ... OutputStream out_Stream = response.getOutputStream(); out_Stream.write( data ); out_Stream.close(); } }
ServletOutputStream servletOutputStream = response.getOutputStream(); byte[] b = new byte[1024]; int i = 0; FileInputStream fis = new java.io.FileInputStream(realName); while ((i = fis.read(b)) > 0)...
用与java web 开发,java 实现的数字验证码的生成 class Image{} *" %> <jsp:useBean id="image" scope="session" class="myclass.test....ImageIO.write(image.creatImage(), "JPEG", response.getOutputStream()); %>