fastjson转换器简介及基本使用

- 日理万妓 2022-01-29 02:57 389阅读 0赞

### 0.简介 ###

FastJson的介绍:
    	Fastjson是一个Java库，可以将Java对象转换为JSON格式，当然它也可以将JSON字符串转换为Java对象。
    	Fastjson可以操作任何Java对象，即使是一些预先存在的没有源码的对象。
    	
    FastJson的特点:
    	1.FastJson数度快,无论序列化和反序列化,都是当之无愧的fast 
    	2.功能强大(支持普通JDK类包括任意Java Bean Class、Collection、Map、Date或enum) 
    	3.零依赖(没有依赖其它任何类库)
    
    FastJson的简单说明:
    	FastJson对于json格式字符串的解析主要用到了下面三个类： 
    		1.JSON：fastJson的解析器，用于JSON格式字符串与JSON对象及javaBean之间的转换 
    		2.JSONObject：fastJson提供的json对象 
    		3.JSONArray：fastJson提供json数组对象

### 1.引入依赖（Spring相关略） ###

<dependency>
    	<groupId>com.alibaba</groupId>
    	<artifactId>fastjson</artifactId>
    	<version>1.2.28</version>
    </dependency>

### 2.Spring-mvc.xml配置 ###

<context:component-scan base-package="com.ronybo.controller" />
    
    <mvc:annotation-driven>
    	<mvc:message-converters register-defaults="true">
    		
    		<bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
    			<property name="supportedMediaTypes">
    				<list>
    					<value>text/html;charset=UTF-8</value>
    					<value>application/json;charset=UTF-8</value>
    				</list>
    			</property>
    		</bean>
    	</mvc:message-converters>
    </mvc:annotation-driven>

### 3.配置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_2_5.xsd" version="2.5">	
       	
    	<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>
    		<init-param>  
                <param-name>forceEncoding</param-name>  
                <param-value>true</param-value>  
            </init-param>  
    	</filter>
    	<filter-mapping>
    		<filter-name>CharacterEncodingFilter</filter-name>
    		<url-pattern>/*</url-pattern>
    	</filter-mapping>	
    	
      	<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:spring/springmvc.xml</param-value>
      		</init-param>
      		<load-on-startup>1</load-on-startup>
      	</servlet>
      
      	<servlet-mapping>
      		<servlet-name>springmvc</servlet-name>
      		<url-pattern>*.do</url-pattern>
     	</servlet-mapping>
    </web-app>

### 4.编写Controller ###

import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.alibaba.fastjson.JSON;
    import com.ronybo.vo.User;
    
    @RestController
    @RequestMapping("/test")
    public class TestController { 
    	@RequestMapping("/testFastJson")
    	public User getUser(String userName, String password) { 
    		User user = new User(111, userName, password);
    		System.out.println(JSON.toJSON(user));
    		return user;
    	}
    }

### 4.编写index.html ###

<!DOCTYPE html>
    <html>
        <head>
            <title>index.html</title>
            <script type="text/javascript" src="js/jquery/jquery.min.js" charset="UTF-8"></script>
        </head>
      
        <body>
            <script type="text/javascript"> $.ajax({ url: "/fastjsondemo/test/testFastJson.do", data: { "userName":"小明","password":"123456"}, type: "post", success : function(response) { // 此时是一个JSON字符串，需要转为JSON对象 console.log(JSON.parse(response)); } }) </script>
        </body>
    </html>

### 5.控制台 ###

![酱紫][20190520201001206.png]

### 6.浏览器 ###

传到后台的数据：  
![asd][]

#### 后台响应的数据： **此时是一个JSON对象。** ####

![asd][asd 1]  
![字符串][20190520201433244.png]

[20190520201001206.png]: /images/20220129/d4e8535ad91c4569a7efce8e41bee34a.png
[asd]: /images/20220129/d851c1fa50424570872d0f5879b3f8a3.png
[asd 1]: /images/20220129/b484b8789ab64021b11d02646fd9a453.png
[20190520201433244.png]: /images/20220129/3a7292a3c0d54af79e03ede62dcc755f.png