JavaEE 考点

response.setContentType("text/html;charset=UTF-8");

req.getParameter("words");

req.getParameterValues("接收多个参数");

PrintWriter out = response.getWriter();

req.getRequestDispatcher("calculator.jsp").forward(req, resp);

response.sendRedirect("http://www.baidu.com");

req.setAttribute("number","hello");

<%@ page contentType="text/html;charset=UTF-8" language="java" import="??,??" %>

@WebServlet(name = "Annotate", urlPatterns = {"/Annotate"})

//javax.servlet.http.cookie
Cookie[] cookies = req.getCookies();
cookie = new Cookie("name","killer");
cookie.setPath(req.getContextPath());
cookie.setMaxAge(30);
resp.addCookie(cookie);

HttpSession session = req.getSession(true);
session.setAttribute("max","1");

String s = (String)getServletContext().getAttribute("temp");

@WebFilter(filterName = "LoginFilter", urlPatterns = {"/Login"})
public class LoginFilter implements Filter{
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {}
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        filterChain.doFilter(servletRequest,servletResponse);
    }
    @Override
    public void destroy() {}
}

public class DatabaseManager {
    private Connection connection;

    public void init(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection =   DriverManager.getConnection("jdbc:mysql://localhost:3306/table?useUnicode=true& characterEncoding=utf8","root","");
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public void close(){
        try {
            connection.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public boolean addOrDeleteOrUpdate(String sql){
        boolean i = true;
        try {
            PreparedStatement ps  = connection.prepareStatement(sql);
            i = ps.execute();
        } catch (Exception e){
            e.printStackTrace();
        }
        return i;
    }
}