解决post请求响应乱码问题

public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        System.out.println("用户名："+req.getParameter("username"));
        System.out.println("密码:"+req.getParameter("password"));

        String[] s = req.getParameterValues("hobby");

        System.out.println("爱好:"+ Arrays.asList(s));
    }
}

设置字符集：

req.setCharacterEncoding("utf-8");