在一个自定义标签中利用out.write输出里一个自定义标签失效

 public void doTag() throws JspException, IOException {
        Book book = null;
        JspContext jc = super.getJspContext();
        JspWriter out = jc.getOut();
        Object value = jc.getAttribute(bookMap);
        //
        if (value instanceof Map) {
            Map<String, Object> bookMap = (Map<String, Object>) value;
            try {
                int row = bookMap.size() - 2;
                for (int i = 0; i < row;) {
                    out.write("<div class='row'>");
                    for (int j = 0; j < 3 && i < row; j++, i++) {
                        book = (Book) bookMap.get("line" + i);
                        out.write("<div class='col-xs-5 col-md-4'>");
                        out.write("<a href='#' >");
                    **_ out.write("<lms:bookpic book_id='"+book.getBook_id()+"' width='160px' height='200px'>");_**
                        out.write("</a>");
                        out.write("<div class='caption'>");
                        out.write("<h4>" + book.getBook_name() + "</h4>");
                        out.write("<p class='text-left text-muted'>"
                                + book.getBook_abstract() + "</p>");
                        out.write("<p>");
                        out.write("<a href='bookServlet?actionCode=modifyBook&book_id="
                                + book.getBook_id()
                                + "' class='btn btn-primary'>修改图书</a>");
                        out.write("<b>&nbsp;</b>");
                        out.write("<a  class='btn btn-info' onclick='deleteBook("+book.getBook_id()+")' >删除图书</a>");
                        out.write("</p>");
                        out.write("</div>");
                        out.write("</div>");
                    }
                    out.write("</div>");
                }

            } catch (final Exception e) {
                e.printStackTrace();
            }
        }
    }