Personnel management system --第二天

接下来实现一些多个模块都要用到的工具类。

 1. 浏览器要经常处理用户的请求，以及响应，所以编码过滤器是有必要实现的。

　　java代码

public class EncodingFilter implements Filter {
    private String encoding="UTF-8";
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        if (filterConfig.getInitParameter("ENCODING")!=null){
            encoding=filterConfig.getInitParameter("Encoding");
        }
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        servletRequest.setCharacterEncoding(encoding);
        servletResponse.setCharacterEncoding(encoding);
        filterChain.doFilter(servletRequest,servletResponse);
    }
    @Override
    public void destroy() {
        encoding=null;
    }
}

 　　在web.xml中的配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
         http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
<!--编码过滤器配置-->
  <filter>
    <filter-name>Encoding</filter-name>
    <filter-class>per.lc.sms.global.EncodingFilter</filter-class>
    <init-param>
      <param-name>ENCODING</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>Encoding</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

2.核心控制器：

规范用户的请求，例如:department/add.do,这个请求经过核心控制器处理后，会去IOC容器中去找名为departmentController的<bean>,我们知道spring中的bean是一个个的java类，然后执行类中名为add的方法，方法中会用到业务层的对象，业务层用到持久层的对象。代码在后续体现。这样做让代码逻辑清晰很多。

public class DispatcherServlet extends GenericServlet {
    private ApplicationContext context=null;
    @Override
    public void init() throws ServletException {
        super.init();
        context=new ClassPathXmlApplicationContext("spring.xml");
    }
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {

        HttpServletRequest request=(HttpServletRequest)servletRequest;
        HttpServletResponse response=(HttpServletResponse)servletResponse;

        String path=request.getServletPath().substring(1);
        String beanName=null;
        String methodName=null;
        int index=path.indexOf('/');
        if(index!=-1){
            beanName=path.substring(0,index)+"controller";
            methodName=path.substring(index+1,path.indexOf(".do"));
        }else{
            beanName="selfController";
            methodName=path.substring(0,path.indexOf(".do"));
        }
        Object obj=context.getBean(beanName);

        try {
            Method method=obj.getClass().getMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);//参数代表目标方法里的参数的类型。复习Java反射的知识
            method.invoke(obj,request,response);//第一个参数代表目标对象（就是执行它里面的方法）
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }

在web.xml中的配置

<servlet>
    <servlet-name>DispatcherServlet</servlet-name>
    <servlet-class>per.lc.sms.global.DispatcherServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>