Servlet的代码优化,让代码具有复用性将代码耦合性降低,每添加一个方法方法就要多添加一个servlet这样很浪费空间,所以我们要把所有方法放在一个类里面,用方法名来判断该用那个方法,这样提高了代码

列如:

每一个添加方法

BrandServletAdd

BrandSelectAll

非常的浪费资源

所以我们把每个方法都提取到一个类里面就想Mapper接口一样

public interface BrandMapper {    @Select("select * from tb_brand")    @ResultMap("brandResultMap")    List selectAll();    @Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")    void add(Brand brand);    @Select("select * from tb_brand where id = #{id}")    @ResultMap("brandResultMap")    Brand selectById(int id);    @Update("update tb_brand set brand_name = #{brandName},company_name = #{companyName},ordered = #{ordered},description = #{description},status = #{status} where id = #{id}")    void Update(Brand brand);    @Delete("delete from tb_brand where id = #{id}")    void deleteById(int id);}

所以我们可以换一种思路来写创建一个类继承

public class BaseServlet extends HttpServlet{}

把方法名字的路径和方法名字写成一样,方待会反射调用方法列如路径名字是selectAll

我们就可以把他当做方法名传给反射里面的 getMethod 就可获取到该方法

这样就不用创建过多的类了案列如下

public class BaseServlet extends HttpServlet {    @Override    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String s = req.getRequestURI(); int i = s.lastIndexOf("/"); String u = s.substring(i + 1); Class aClass = this.getClass(); try {     Method method = aClass.getMethod(u, HttpServletRequest.class, HttpServletResponse.class);     method.invoke(this,req,resp); } catch (NoSuchMethodException e) {     e.printStackTrace(); } catch (InvocationTargetException e) {     e.printStackTrace(); } catch (IllegalAccessException e) {     e.printStackTrace(); }    }}

 以上是获取地址然后拆分获取到路径最后一位,就是方法名字啦

然后在设置一个类比如Brand继承着现在这个类

@WebServlet("/brand/*")public class BrandServlet extends BaseServlet{    private BrandServletImpl bs = new BrandServletImpl();    public void selectAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { List brands = bs.selectAll(); String s = JSON.toJSONString(brands); response.setContentType("text/json;charset=utf-8"); response.getWriter().write(s);    }    public void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { BufferedReader reader = request.getReader(); String s = reader.readLine(); System.out.println(s); Brand brand = JSON.parseObject(s, Brand.class); BrandServletImpl brandServlet = new BrandServletImpl(); brandServlet.add(brand); response.getWriter().write("ok");    }}

记住路径一定要 /brand/* 用通配符这样可以接收一切的路径

总结:每添加一个方法方法就要多添加一个servlet这样很浪费空间,所以我们要把所有方法放在一个类里面,用方法名来判断该用那个方法,这样提高了代码的复用性