Home > Developer > Web Develop

Vi. interacting with JSON

Source: Internet
Author: User
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

1. Two modes of interaction

　　

Shows the two formats for requesting data from a client, one that requests JSON data directly, and the other is Key/value data. But no matter what kind of data the request is, it is convenient to parse the result on the front page. Eventually we all convert to JSON data format.

Back to Top 2, import the corresponding jar package (see source for details)

Back to Top 3. Configure the JSON converter in the Springmvc.xml file

　　The first method:

1 <mvc:annotation-driven ></mvc:annotation-driven>

The second method:

12345678910111213141516171819 <!-- 用于将对象转换为 JSON  --> <bean id="stringConverter"    class="org.springframework.http.converter.StringHttpMessageConverter">     <property name="supportedMediaTypes">         <list>             <value>text/plain;charset=UTF-8</value>         </list>     </property> </bean> <bean id="jsonConverter"class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"></bean> <bean      class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">     <property name="messageConverters">         <list>             <ref bean="stringConverter"/>             <ref bean="jsonConverter"/>         </list>     </property> </bean>

　　

Back to top 4, request for JSON data test

Here we need to take note of two annotations:

　　@ResponseBody convert the background Pojo to a JSON object and return to the page.

@RequestBody accept the foreground JSON data and automatically encapsulate the JSON data Pojo.

①, JSP page

1234567891011121314151617181920212223242526272829303132333435 <%@ page language="java"contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"><meta http-equiv="Content-Type"content="text/html; charset=UTF-8"><title>SpringMVC和 json 交互</title><script type="text/javascript"src="${pageContext.request.contextPath}/js/jquery-2.1.4.min.js"></script><script type="text/javascript">    var dataJson = {            ‘username‘:‘Bob‘,            ‘sex‘:‘男‘    };    function requestJson(){        $.ajax({            type:"POST",            url:"${pageContext.request.contextPath}/requestJson",            //指定数据格式为 json            contentType:"application/json;charset=UTF-8",            data:JSON.stringify(dataJson),            dataType:"json",            success:function(data){                console.log(data.username);                console.log(data.sex);            }        });    }    </script><body>    <button onclick="requestJson()"value="请求是json,返回json">请求是json,返回json</button>    </body>

　　

②, Controller

123456789101112131415161718192021222324 packagecom.ys.controller;importorg.springframework.stereotype.Controller;importorg.springframework.web.bind.annotation.RequestBody;importorg.springframework.web.bind.annotation.RequestMapping;importorg.springframework.web.bind.annotation.ResponseBody; importcom.ys.po.User;@ControllerpublicclassUserController {            //请求为json,返回json    @RequestMapping("/requestJson")    //@RequestBody将请求信息的json串转成user对象    //@ResponseBody将user对象转成json输出    @ResponseBody    publicUser requestJson(@RequestBodyUser user) throwsException{        System.out.println(user);        returnuser;//由于@ResponseBody注解，将user转成json格式返回    }    }

③, testing

We visit the JSP page above and click on the button to enter the Controller

　　

Then we look at the returned data:

　　

Back to top 5, request for Key/value data test

①, JSP page

②, Controller

12345678 //请求为key/value,返回json    @RequestMapping("/requestKeyValue")    //@RequestBody将请求信息的json串转成user对象    @ResponseBody    publicUser requestKeyValue(User user) throwsException{        System.out.println(user);        returnuser;    }

③, testing

　　

Then return the data:

　　

Back to top 6, problems encountered

　　①, the following code, because we use Ajax submissions, we introduced a jquery file on the JSP page, found that no matter the absolute path or relative path, the system will always find this file?

1 <script type="text/javascript"src="${pageContext.request.contextPath}/js/jquery-2.1.4.min.js"></script>

Cause: Because you are in the Web. xml file, the configuration for the filter is to intercept all requests. So a file similar to *.js, or *.CSS, is intercepted, so it can't be accessed.

　　

Workaround:

The first approach: we can use the interceptor configured above to intercept only *.do, or *.action, instead of "/". Then the SPRINGMVC container will not intercept files such as *.JS,*.CSS. But this style does not support Restful, it is recommended not to adopt.

Second method: Configure the Interceptor's filtering request in Web. xml

123456789 <!--要写在DispatcherServlet的前面， 让 defaultServlet先拦截请求，这样请求就不会进入Spring了，我想性能是最好的吧。-->     <servlet-mapping>         <servlet-name>default</servlet-name>         <url-pattern>*.css</url-pattern>     </servlet-mapping>     <servlet-mapping>         <servlet-name>default</servlet-name>         <url-pattern>*.js</url-pattern>     </servlet-mapping> 

Third approach: Configure non-filtering of static resources in Spingmvc.xml

123 <!-- 配置静态文件过滤器 -->    <mvc:resources location="/WEB-INF/css/"mapping="/css/**"/>    <mvc:resources location="/WEB-INF/js/"mapping="/js/**"/>

　　

　　②, is also more prone to make mistakes 415

　　

　　

There are many reasons for this error. We need a step-by-Step troubleshooting:

The first step: you must ensure that the imported Jackson-related jar packages are full.

The second step: the configuration of the JSON converter in the Springmvc.xml file must not be missing, how to view this blog's 3rd

Step three: When writing an AJAX request. ContentType: "Application/json;charset=utf-8", do not write ContentType this attribute

Fourth step: Ajax to the background do not pass the string directly, to convert to JSON, that is data:JSON.stringify (Datajson),

Vi. interacting with JSON

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
ajax with json in php redhat vi vi php ubuntu vi vi filename webservices in php with json example vi bashrc

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More