zoukankan      html  css  js  c++  java
  • springMVC学习总结(三)数据绑定

    springMVC学习总结(三)数据绑定

    一、springMVC的数据绑定,常用绑定类型有:

    1、servlet三大域对象:

    • HttpServletRequest
    • HttpServletResponse
    • HttpSession

    2、Model的方式

    • 类型:

      • Model

         @Controller
         public class Demo01Controller {
             @RequestMapping(value = "test.action")
             public String test(Model md){
                 md.addAttribute("name","xujie");
                 return "test";
             }
         }
        
      • ModelMap

         @Controller
         public class Demo01Controller {
             @RequestMapping(value = "test.action")
             public String test(ModelMap mp){
                 mp.addAttribute("name","xujie");
                 return "test";  //字符串是返回页面的页面名
             }
         }
        
      • ModelAndView

         @Controller
         public class Demo01Controller {
             @RequestMapping(value = "test.action")
             public ModelAndView test(ModelAndView mv){
                 mv.addObject("name","xujie");
                 mv.setViewName("test");
                 return mv;
             }
         }
        
    • 前台页面jsp编码

        	<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
        	<%@page isELIgnored="false" %>
        	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        	"http://www.w3.org/TR/html4/loose.dtd">
        	<html>
        	<head>
        	    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        	    <title>Hello World</title>
        	</head>
        	<body>
        	1、姓名:${requestScope.name }<br/>
        	</body>
        	</html>
      
    • 总结:

      • Model和ModelMap类型的model,都要在参数列表中声明。
      • ModelAndView可以不用在参数列表中声明,但是最后的跳转页面一定要通过ModelAndView.setViewName()的方式跳转,否则页面可以成功跳转,但是取不到后台设置的值。

    3、绑定简单数据类型

    • 用法:

      • 示例一:

          //在处理器形参位置声明简单数据类型,处理器直接获取
          @Controller
          public class Demo01Controller {
              @RequestMapping(value = "test.action")
              public String test(String name){
                  System.out.println("获取到前台的值是:"+name);
                  return "test";
              }
          }
        
      • 支持的简单绑定类型:

        • 整型(int、Integer)
        • 字符串(String)
        • 单精度(Float、float)
        • 双精度(Double、double)
        • 布尔型(true、false)
    • @RequestParam用法:

      • @RequestParam 有三个常用属性值:
        • value:绑定参数的变量名

        • defaultValue:如果没有传这个值,默认取值

        • required:该变量是否必须要有
          示例:

            @Controller
            public class Demo01Controller {
                @RequestMapping(value = "test.action")
                public String test(@RequestParam(value = "name",defaultValue = "xujie",required = false) String name){
                    System.out.println("name="+name);
                    return "test";
                }
            }
          

    4、绑定pojo(简单的java对象)类型

    Student类:(pojo)

    	public class Student {
    	    private String name;
    	    private int age;
    	
    	    get/set...
    	}
    

    Controller类:

    	@Controller
    	public class Demo01Controller {
    	    @RequestMapping(value = "test.action",method = RequestMethod.POST)
    	    public String test(Student stu){
    	        System.out.println("学生姓名:"+stu.getName());
    	        System.out.println("学生年龄:"+stu.getAge());
    	        return "test";
    	    }
    	}
    + *这里我是用的postman做的请求测试,所以此处不列举前台是如何发送请求的了,只要是post请求,并且参数名分别为name和age就可以获取到;*
    

    5、绑定包装对象(对象里面有对象)

    Courses类(pojo):

    package com.springMVC.pojo;
    
    public class Courses {
        private String coursesName;
        private String teacher;
    
        get/set...
    }
    

    Courses类(pojo):

    package com.springMVC.pojo;
    
    public class Student {
        private String name;
        private int age;
        private Courses courses;
    
       get/set...
    }
    

    Controller类:

    @Controller
    public class Demo01Controller {
        @RequestMapping(value = "test.action",method = RequestMethod.POST)
        public String test(Student stu){
            System.out.println("学生姓名:"+stu.getName());
            System.out.println("学生年龄:"+stu.getAge());
            System.out.println("课程名称"+stu.getCourses().getCoursesName());
            System.out.println("课程老师"+stu.getCourses().getTeacher());
            return "test";
        }
    }
    

    6、绑定数组(以字符串数组为例)

    直接绑定数组类型参数

    Controller类:

    @Controller
    public class Demo01Controller {
        @RequestMapping(value = "test.action",method = RequestMethod.POST)
        public String test(String[] strs){
            for (String str:strs ) {
                System.out.println(str);
            }
            return "test";
        }
    }
    

    接口测试:

    通过pojo属性的方式绑定数组

    pojo类:

    package com.springMVC.pojo;
    
    public class Student {
        private String name;
        private int age;
        private Courses courses;
        private String[] friends;
    
        get/set...
    }
    

    Controller类:

    @Controller
    public class Demo01Controller {
        @RequestMapping(value = "test.action",method = RequestMethod.POST)
        public String test(Student stu){
            String[] friends = stu.getFriends();
            for (String str:friends ) {
                System.out.println(str);
            }
            return "test";
        }
    }
    

    接口测试

    7、绑定List

    接收页面数据

    接收页面数据的时候,list必须声明为某一个pojo的属性才可以接收到
    pojo类:

    package com.springMVC.pojo;
    
    import java.util.List;
    
    public class Student {
        private String name;
        private int age;
        private Courses courses;
        private List<String> friends;   //pojo的list
    
        get/set...
       
    }
    

    Controller类:

    @Controller
    public class Demo01Controller {
        @RequestMapping(value = "test.action",method = RequestMethod.POST)
        public String test(Student student){
            List<String> friends = student.getFriends();
            for (String str : friends) {
                System.out.println(str);
            }
            return "test";
        }
    }
    

    接口测试:

    向页面传递数据

    Controller类:
    此处以ModelMap的方式向页面传递数据

    @Controller
    public class Demo01Controller {
        @RequestMapping(value = "test.action",method = RequestMethod.GET)
        public String test(ModelMap modelMap){
            //ModelMap modelMap = new ModelMap();
            Student student = new Student();
            ArrayList<String> list = new ArrayList<String>();
            list.add("xujie1");
            list.add("xujie2");
            list.add("xujie3");
            list.add("xujie4");
            student.setFriends(list);
            student.setName("yuanxiliu");
            modelMap.addAttribute("student",student);
            return "test";
        }
    }
    

    jsp页面:

    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
    <%@page isELIgnored="false" %>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Hello World</title>
    </head>
    <body>
        <c:forEach items="${student.friends}" var="friend" varStatus="state" >
    
            ${friend}<%--循环输出List--%>
    
        </c:forEach>
    </body>
    </html>
    

    页面结果:

    8、绑定Map

    跟list类似,同样必须定义成某个pojo的属性才可以绑定数据:
    pojo类:

    package com.springMVC.pojo;
    
    import java.util.HashMap;
    import java.util.List;
    
    public class Student {
        private String name;
        private int age;
        private Courses courses;
        private HashMap<String,String> parents;
    
        get/set...
    }
    

    Controller类:

    @Controller
    public class Demo01Controller {
        @RequestMapping(value = "test.action",method = RequestMethod.POST)
        public String test(Student student){
            String father = student.getParents().get("father");
            String mother = student.getParents().get("mother");
            System.out.println("父亲是:"+father);
            System.out.println("母亲是:"+mother);
            return "test";
        }
    }
    

    接口测试:

  • 相关阅读:
    [Linux] day04——Linux 入门
    react 资源汇总
    画原型图工具
    Atom 插件安装
    react 编写组件 五
    webstom 配置git 后左侧菜单栏配色调整
    Webstorm 不识别es6 import React from ‘react’——webstorm不支持jsx语法怎么办
    Es6 之for of
    一个react的完整项目展示
    前后端分离 接口管理神器——Rap本地搭建
  • 原文地址:https://www.cnblogs.com/xujie09/p/8110656.html
Copyright © 2011-2022 走看看