微信小程序填坑之路之springmvc与小程序的数据交互(json)

  • • 发表于 4周前
  • • 作者 toBeMN
  • • 228 次浏览
  • • 2 条评论
  • • 最后编辑时间 4周前
  • • 来自 [技术]

原创声明:本文为作者原创,未经允许不得转载,经授权转载需注明作者和出处

springmvc框架写到现在终于牵扯到小程序了(所以别说我“不务正业”),对于一个应用程序来说,它的本质其实就是无数个对数据进行增删改查的操作,这里起到至关重要的就是数据,于是这篇帖子的目的就是实现小程序与后台数据的交互。

小程序使用的是wx.request的api来提交和接收数据,最常见的就是接收后台传过来的json数据,并对其进行解析

先看运行结果:

这里总结springmvc框架的三种转json方法

后台 前台 返回前台的json格式
对象/bean/实体类 json {“id”: 0,”username”: “”,”age”: 0}
List<实体类> json [{“id”:1,”username”:”2”,”age”:1},{“id”:2,”username”:”3”,”age”:2}]
Map<String,实体类> json {“success”:true,”detail”:[ ] }

按步骤,从头开始来:

后台

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:config/ybajax.xml</param-value>
      </init-param>
  </servlet>
  <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>*.mn</url-pattern>
  </servlet-mapping>
  <filter>
      <filter-name>CharacterEncodingFilter</filter-name>
      <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
      <init-param>
          <param-name>encoding</param-name>
          <param-value>UTF-8</param-value>
      </init-param>
  </filter>
  <filter-mapping>
      <filter-name>CharacterEncodingFilter</filter-name>
      <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

导入springmvc所需要的jar包:http://pan.baidu.com/s/1jIK6sb8
导入json所需要的jar包:http://pan.baidu.com/s/1i5bnggP

配置文件 ybajax.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans 
      xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:mvc="http://www.springframework.org/schema/mvc"
      xmlns:context="http://www.springframework.org/schema/context"
      xsi:schemaLocation="http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
      http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.0.xsd">
    <context:component-scan base-package="action"/>
    <!-- 注册适配器 -->
    <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="messageConverters">
            <list>
                <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean>
            </list>
        </property>
    </bean>
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

注意json需要对应的适配器类

实体类:User.java (实现bean用到)和 Bean.java(实现List、Map用到)

package bean;
public class User {
    private int id;
    private String username;
    private int age;
    public User() {}
    public User(int id, String username, int age) {
        this.id = id;
        this.username = username;
        this.age = age;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

package bean;
import java.util.ArrayList;
import java.util.List;
public class Bean {
    private List<User> listuser= new ArrayList<User>();
    private Bean(){}
    public List<User> getListuser() {
        return listuser;
    }
    public void setListuser(List<User> listuser) {
        this.listuser = listuser;
    }
}

AjaxAction.java

package action;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import bean.Bean;
import bean.User;
@Controller
@RequestMapping("/user")
public class YbAjaxAction{
    @RequestMapping(method=RequestMethod.POST,value="/bean2json")
    public @ResponseBody User bean2json(User user){
        return user;
    }
    @RequestMapping(method=RequestMethod.POST,value="/listbean2json")
    public @ResponseBody List<User> listbean2json(Bean bean){
        List<User> listuser=bean.getListuser();
        return listuser;
    }
    @RequestMapping(method=RequestMethod.POST,value="/mapbean2json")
    public @ResponseBody Map<String,Object> mapbean2json(Bean bean){
        List<User> listuser=bean.getListuser();
        Map<String, Object> mapuser=new HashMap<String, Object>();
        mapuser.put("success",true);
        mapuser.put("detail",listuser);
        return mapuser;
    }
    //表单提交
    @RequestMapping(method=RequestMethod.POST,value="/json2json")
    public @ResponseBody User bean2json(@RequestBody Map<String, String> map){
        String username="";
        int age=0;
        if(map.containsKey("username")){
            username=map.get("username");
        }
        if(map.containsKey("age")){
            age=Integer.parseInt(map.get("age"));
        }
        User user=new User(1,username,age);
        return user;
    }
}

@ResponseBody: 该注解用于将Controller的方法返回的对象,通过适当的HttpMessageConverter转换为指定格式后,写入到Response对象的body数据区(用于返回json数据给页面)
@RequestBody : 该注解用于读取Request请求的body部分数据,使用系统默认配置的HttpMessageConverter进行解析,然后把相应的数据绑定到要返回的对象上;再把HttpMessageConverter返回的对象数据绑定到 controller中方法的参数上(用于接收前台的数据)

前台

index.wxml

<view class="container">
  <button bindtap="bean_json" class="btn">bean_json</button>
  <button bindtap="listbean_json" class="btn">listbean_json</button>
  <button bindtap="mapbean_json" class="btn">mapbean_json</button>
  <view class="line"></view>
  <form bindsubmit="json_json">
    <view>
      <view >username</view>
      <input name="username" type="text" class="input_bg"/>
    </view>
    <view>
      <view >age</view>
      <input name="age" type="text" class="input_bg"/>
    </view>
    <button formType="submit" class="btn">json_json</button>
  </form>
  <text>{{show}}</text>
</view>

index.wxss

.container {
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: 20rpx;
} 
.input_bg{
    background-color: #F8F8F8;
    border-radius: 10rpx;
}
.btn{
    background-color: #A65353;
    margin: 20rpx;
    border-radius: 10rpx;
    color:#F8F8F8;
}
.line{
    height: 1rpx;
    width: 100%;
    background-color: #A65353;
    margin: 30rpx 0;
}

index.js

var app = getApp()
Page({
  data: {
    show:""
  },
  bean_json: function() {
    var that=this;
    wx.request({
      url: 'http://localhost:8080/springMVC/user/bean2json.mn',
      data: {
        id:1,
        username:"toBeMN",
        age:28
      },
      method: 'POST', 
      header: {
        "Content-Type":"application/x-www-form-urlencoded"
      },
      success: function(res){
        var show="对象转json 
 username:"+res.data.username+
        "
 age:"+res.data.age;
        that.setData({
          show:show
        })
      }
    })
  },
  listbean_json: function() {
    var that=this;
    wx.request({
      url: 'http://localhost:8080/springMVC/user/listbean2json.mn',
      data: {
        'listuser[0].username':"Hello",
        'listuser[0].age':18,
        'listuser[1].username':"World",
        'listuser[1].age':28
      },
      method: 'POST', 
      header: {
        "Content-Type":"application/x-www-form-urlencoded"
      },
      success: function(res){
        var show="list<对象>转json ";
        for(var i=0;i<res.data.length;i++){
          show+="
 username:"+res.data[i].username+
          "
 age:"+res.data[i].age;
        }
        that.setData({
          show:show
        })
      }
    })
  },
  mapbean_json: function() {
    var that=this;
    wx.request({
      url: 'http://localhost:8080/springMVC/user/mapbean2json.mn',
      data: {
        'listuser[0].username':"Hello",
        'listuser[0].age':48,
        'listuser[1].username':"MINA",
        'listuser[1].age':58
      },
      method: 'POST', 
      header: {
        "Content-Type":"application/x-www-form-urlencoded"
      },
      success: function(res){
        var show="map<String,Obiect>转json ";
        for(var i=0;i<res.data.detail.length;i++){
          show+="
 username:"+res.data.detail[i].username+
          "
 age:"+res.data.detail[i].age;
        }
        that.setData({
          show:show
        })
      }
    })
  },
  json_json: function(res) {
    var that=this;
    console.log(res.detail.value)
    wx.request({
      url: 'http://localhost:8080/springMVC/user/json2json.mn',
      data: res.detail.value,
      method: 'POST', 
      header: {
        "Content-Type":"application/json"
      },
      success: function(res){
        var show="表单提交返回json 
 username:"+res.data.username+
        "
 age:"+res.data.age;
        that.setData({
          show:show
        })
      }
    })
  },
  onLoad: function () {
  }
})

所有的映射处理都交由框架,我们只需要设置对的属性名、变量名,即可自动赋值
例如表单提交,这个应该是最常用的,因为小程序form提交后会将表单中的数据存入一个json串(如果表单中input的name没有写,则不会有数据,这是小程序内部映射的神奇之处),所以使用request请求的时候可以直接将json串传到后台解析,后台处理完业务在将结果json传回前台,这就是一个交互的过程。

如有不理解可以提出,yeah!

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toBeMN

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