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json jackson

2024-08-16 02:39:22   217人阅读

 

1.引入依赖

        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-databind</artifactId>            <version>2.8.3</version>        </dependency>

 

2.添加 conventer

    <mvc:annotation-driven>        <mvc:message-converters>            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">                <property name="objectMapper" ref="objectMapper" />            </bean>        </mvc:message-converters>    </mvc:annotation-driven>    <bean id="objectMapper" class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean"        p:indentOutput="false" p:simpleDateFormat="yyyy-MM-dd‘T‘HH:mm:ss.SSSZ" />

 

indentOutput 缩进打印，false 无缩进 ，true 有缩进（格式化）

{  "b" : "你好",  "a" : "2016-10-06T14:54:16.918+0800"}

 

{"b":"你好","a":"2016-10-06T14:57:33.724+0800"}

 

simpleDateFormat 可以将日期类型自动转为指定格式字符串

 

具体用法可以查看该类

 

MappingJackson2HttpMessageConverter

By default, this converter supports application/json and application/*+json with UTF-8 character
set. This can be overridden by setting the supportedMediaTypes property.

这样重写

    <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">        <property name="supportedMediaTypes">            <list>                <value>application/json;charset=UTF-8</value>            </list>        </property>    </bean>

 

3. 设置controller 的 response

关于controller 返回时由哪个 conventer 处理的问题

首先 如果不是加 @ResponseBody 则由viewresolver 处理

在 @Controller + @ResponseBody = @RestController

You can use the new @RestController annotation with Spring MVC applications, removing the need to add @ResponseBody to each of your @RequestMapping methods.

这种情况下 converter就生效了，会根据 Content-Type:text/html;charset=ISO-8859-1 类型分配给具体的 converter 处理

默认有一个 

2016-10-06 15:39:48 DEBUG RequestResponseBodyMethodProcessor:250 - Written [你好] as "text/html" using [org.springframework.http.converter.StringHttpMessageConverter@407305a3]

这个默认的 StringHttpMessageConverter 使用的编码是 

public static final Charset DEFAULT_CHARSET = Charset.forName("ISO-8859-1");

可以覆盖这个 converter

            <bean class="org.springframework.http.converter.StringHttpMessageConverter">                <constructor-arg value="UTF-8" />            </bean>

 

 

技术分享

 

有这么多 HttpMessageConverter 视情况增加到 <mvc:message-converters>...

 

json jackson


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