接收客户端表单数据，并将其封装为对象

港控/mmm° 2024-03-23 14:25 70阅读 0赞

一、定义实体类

public class UserBean {
        private Integer id ;
        private String name;
        @JsonFormat(pattern = "yyyy-MM-dd")//指定对象序列化为JSON时的日期格式
        private LocalDate birthday;
        private Integer money;
        private Double payTaxes;
    }

二、html表单

三、业务组件

public class AddServlet extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            this.doPost(req, resp);
        }
    
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            req.setCharacterEncoding("utf-8");
            resp.setContentType("text/html;charset=utf-8");
            //将表单数据封装为用户对象
            UserBean user = new UserBean();
            System.out.println(user);
            this.fullBean(user,req);
            resp.getWriter().println(user.toString());
        }
        //
        private void fullBean(Object object,HttpServletRequest request){
            //得到表单数据的键名
            Enumeration<String> en =request.getParameterNames();
            try {
                while (en.hasMoreElements()){//判断是否有下一个元素
                //取出下一个元素
                String str = en.nextElement();
                //根据表单名，得到表单值
                String value = request.getParameter(str);
                //注意：属性名和表单名 必须一致
    
                    //根据属性名，得到属性值
                    Field f = object.getClass().getDeclaredField(str);
                    f.setAccessible(true);
                    //根据不同的属性类型 完成类型转换
                    if(f.getType() == String.class){
                        f.set(object,value);
                    } else if (f.getType() == int.class || f.getType()==Integer.class) {
                        f.set(object,Integer.parseInt(value));
                    } else if (f.getType()==double.class||f.getType()==Double.class) {
                        f.set(object,Double.parseDouble(value));
                    } else if (f.getType()== LocalDate.class) {
                        f.set(object,LocalDate.parse(value));
                    } else if(f.getType()==String[].class){
                        f.set(object,request.getParameterValues(str));
                    }
    
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

*  getParameter() 根据表单名，得到表单值，注意有多个name属性时它取的是第一个值
 *  getParameterValues（）得到数组 （复选框/列表框就需要用它）

四、启动

public class MainTomcat {
        public MainTomcat(){
            Tomcat tomcat = new Tomcat();
            //设置启动端口
            tomcat.setPort(9090);
            //引导http引擎
            tomcat.getConnector();
            //创建上下文对象
            Context context = tomcat.addContext("",null);
          
            //注册servlet
            Wrapper w1= Tomcat.addServlet(context,"add",new AddServlet());
            w1.setLoadOnStartup(1);
            w1.addMapping("/add");
            try {
                //启动tomcat
                tomcat.start();
            } catch (LifecycleException e) {
                throw new RuntimeException(e);
            }
        }
    
        public static void main(String[] args) {
            new MainTomcat();
        }
    }