hibernate读取oracle数据库里的blob时出现错误，麻烦各位帮忙看看

循环执行下面的代码时
ImageInfo image = imgService.findEntityById(ImageInfo.class, id);
InputStream is = null;
        Blob img = image.getImg();
        try {
            if(img != null){
                is = img.getBinaryStream();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        if (is != null) {
            int len = 0;
            byte[] buffer = new byte[1024];
            HttpServletResponse response = this.getResponse();
            OutputStream out = response.getOutputStream();
            while ((len = is.read(buffer)) != -1) {
                out.write(buffer, 0, len);
            }
            out.flush();
            out.close();
            response.flushBuffer();
            is.close();
        }
出现异常



java.sql.SQLException: 关闭的连接
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146)
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:208)
	at oracle.sql.BLOB.getDBAccess(BLOB.java:955)
	at oracle.sql.BLOB.getBinaryStream(BLOB.java:229)
	at sun.reflect.GeneratedMethodAccessor333.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.hibernate.engine.jdbc.SerializableBlobProxy.invoke(SerializableBlobProxy.java:74)
	at $Proxy1070.getBinaryStream(Unknown Source)
	at com.hzfc.soar.lsjz.jd.action.ZlAction.writeImg(ZlAction.java:194)
	at sun.reflect.GeneratedMethodAccessor379.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at com.opensymphony.xwork.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:358)
	at com.opensymphony.xwork.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:218)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:192)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:175)
	at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:115)
	at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.webwork.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:174)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
	at com.opensymphony.xwork.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:151)