Servlet POST中文乱码问题

Question

tomcat启动没有问题的，但是过1-2天就会乱码了；tomcat重启就好了，再过1-2天又乱码...无限递归。
代码是这样的：

public void doPost(HttpServletRequest req, HttpServletResponse resp)...
{
            // 这边解决跨域
    resp.setHeader("Access-Control-Allow-Origin", "*");
    resp.setHeader("Access-Control-Allow-Methods", "POST");

    req.setCharacterEncoding("utf-8");
    resp.setContentType("text/html;charset=utf-8");

    PrintWriter out = resp.getWriter();

    String bookName = req.getParameter("book");
            // 这边是把接收的参数写到数据库假装![图片说明](https://img-ask.csdn.net/upload/201705/09/1494289706_46397.png)LOG
    SQLHelper.insertUpdate("INSERT INTO `temp` (`name`, `fileName`) VALUES ('" +
            bookName + "', 'SearchBook.java')");
    }

Answer 1

tomcat版本低于8，在tomcat/conf/srver.xml里面，修改为 connectionTimeout="20000"
redirectPort="8443" URIEncoding="UTF-8" />