HTTP的序列化和反序列化
Netty中的Decoder和Encoder就有两种基本层次,层次低的一种是Byte <—> Message,二进制与程序内部消息对象之间的转换,就是常见的序列化/反序列化;另外一种是 Message <—> Message,程序内部对象之间的转换,比较高层次的序列化/反序列化。
Http协议的处理过程,TCP字节流 <—> HttpRequest/HttpResponse <—> 内部对象,就涉及这两种序列化。在springmvc中第一步已经由Servlet容器(tomcat等等)帮我们处理了,第二步则主要由框架帮我们处理。上面所说的Http序列化/反序列化就是指的这第二个步骤,它是controller层框架的核心功能之一,有了这个功能,就能大大减少代码量,让controller的逻辑更简洁清晰,就像上面示意的代码那样,方法中只有一行代码。spirngmvc进行第二步操作,也就是Http序列化和反序列化的核心是HttpMessageConverter。
Springboot配置FastJsonHttpMessageConverter有两种方法:
方法1
启动类继承extends WebMvcConfigurerAdapter,然后覆盖方法configureMessageConverters
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.apache.log4j.Logger;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.context.annotation.Bean;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import java.util.ArrayList;
import java.util.List;
/** springboot以fastjon方式转化json数据 */
@SpringBootApplication
public class Application extends WebMvcConfigurerAdapter {
private static Logger logger = Logger.getLogger(Application.class);
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
super.configureMessageConverters(converters);
//1.需要定义一个convert转换消息的对象;
FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();
//2.添加fastJson的配置信息,比如:是否要格式化返回的json数据;
FastJsonConfig fastJsonConfig = new FastJsonConfig();
SerializerFeature[] serializerFeatures = new SerializerFeature[]{
// 输出key是包含双引号
// SerializerFeature.QuoteFieldNames,
// 是否输出为null的字段,若为null 则显示该字段
// SerializerFeature.WriteMapNullValue,
// 数值字段如果为null,则输出为0
SerializerFeature.WriteNullNumberAsZero,
// List字段如果为null,输出为[],而非null
SerializerFeature.WriteNullListAsEmpty,
// 字符类型字段如果为null,输出为"",而非null
SerializerFeature.WriteNullStringAsEmpty,
// Boolean字段如果为null,输出为false,而非null
SerializerFeature.WriteNullBooleanAsFalse,
// Date的日期转换器
SerializerFeature.WriteDateUseDateFormat,
// 循环引用
SerializerFeature.DisableCircularReferenceDetect,
};
fastJsonConfig.setSerializerFeatures(serializerFeatures);
//3处理中文乱码问题
List<MediaType> fastMediaTypes = new ArrayList<>();
fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
//4.在convert中添加配置信息.
fastJsonHttpMessageConverter.setSupportedMediaTypes(fastMediaTypes);
fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);
//5.将convert添加到converters当中.
converters.add(fastJsonHttpMessageConverter);
}
public static void main(String[] args) {
SpringApplication.run(Application.class,args);
logger.info("=====spring boot start success====");
}
}
方法2
添加配置类来注入Bean:HttpMessageConverters
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import java.nio.charset.Charset;
@Configuration
public class HttpMessageConverterConfig {
//引入Fastjson解析json,不使用默认的jackson
//必须在pom.xml引入fastjson的jar包,并且版必须大于1.2.10
@Bean
public HttpMessageConverters fastJsonHttpMessageConverters() {
//1、定义一个convert转换消息的对象
FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
//2、添加fastjson的配置信息
FastJsonConfig fastJsonConfig = new FastJsonConfig();
SerializerFeature[] serializerFeatures = new SerializerFeature[]{
// 输出key是包含双引号
// SerializerFeature.QuoteFieldNames,
// 是否输出为null的字段,若为null 则显示该字段
// SerializerFeature.WriteMapNullValue,
// 数值字段如果为null,则输出为0
SerializerFeature.WriteNullNumberAsZero,
// List字段如果为null,输出为[],而非null
SerializerFeature.WriteNullListAsEmpty,
// 字符类型字段如果为null,输出为"",而非null
SerializerFeature.WriteNullStringAsEmpty,
// Boolean字段如果为null,输出为false,而非null
SerializerFeature.WriteNullBooleanAsFalse,
// Date的日期转换器
SerializerFeature.WriteDateUseDateFormat,
// 循环引用
SerializerFeature.DisableCircularReferenceDetect,
};
fastJsonConfig.setSerializerFeatures(serializerFeatures);
fastJsonConfig.setCharset(Charset.forName("UTF-8"));
//3、在convert中添加配置信息
fastConverter.setFastJsonConfig(fastJsonConfig);
//4、将convert添加到converters中
HttpMessageConverter<?> converter = fastConverter;
return new HttpMessageConverters(converter);
}
}