记录一下 SpringBoot2.1.4 重写WebSocketConfigurer类下的configureMessageConverters()方法导致Content type 'application/json;charset=UTF-8' not supported的问题

Author： JiuyeXD
发布时间：April 8, 2022
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One comment
976 words
Categories：技术杂谈闲言碎语

## 1. 问题

由于以前开发人员开发websocket相关模块的时候 继承了 `WebSocketConfigurer` 类, 重写了该类下面的 `configureMessageConverters()`方法 作用是解决响应头的`content-type`为`UTF-8`

接下来看代码

```
public class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
    /**
    * @Author: JiuyeXD
    * @Date: 2022/4/7 11:32
    * @Description: TODO 详情转到 {@link ai.config.WebAppConfig}
    */
    @Bean
    public HttpMessageConverter<String> responseBodyConverter() {
        StringHttpMessageConverter converter = new StringHttpMessageConverter(Charset.forName("UTF-8"));
        return converter;
    }

@Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        super.configureMessageConverters(converters);
        converters.add(responseBodyConverter());
    }
}
```

后来注释了该段代码后发现返回的响应头变成了 ISO 然后中文字符全部变成了`?`

![image.png](https://old.qwq.ro/usr/uploads/2022/04/2419809462.png)

## 2. 解决

参考[记一次 SpringBoot2.x 配置 Fastjson 的坑](https://www.jianshu.com/p/cff237cd5a70)的经验

新继承了`WebMvcConfigurationSupport`类 重写了下面的几个方法

一并处理了字符集还有日期格式还有*Long*长度*大于*17位时会出现精度丢失的问题

```
import com.alibaba.fastjson.serializer.SerializeConfig;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.serializer.ToStringSerializer;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import com.alibaba.fastjson.support.spring.messaging.MappingFastJsonMessageConverter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

import java.math.BigInteger;
import java.nio.charset.Charset;
import java.util.List;

/**
 * <p>
 * WebAppConfig - webapp配置
 * TODO 解决 {@link ai.websocket.WebSocketConfig} 产生的 {@link org.springframework.web.bind.annotation.RequestBody} 注解失效的问题
 * </p>
 *
 * @author JiuyeXD
 * @version 1.0
 * @since 2022/4/7
 */
@Configuration
public class WebAppConfig extends WebMvcConfigurationSupport {

@Bean
    public HttpMessageConverter<String> responseBodyConverter() {
        StringHttpMessageConverter converter = new StringHttpMessageConverter(Charset.forName("UTF-8"));
        return converter;
    }

/**
     * @Author: JiuyeXD
     * @Date: 2022/4/7 11:30
     * @Description: TODO 定义一个convert转换消息的对象
     * @return {@link MappingFastJsonMessageConverter}
     */
    public FastJsonHttpMessageConverter messageConverter() {
        FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
        /* 添加fastjson的配置信息 */
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(
                SerializerFeature.PrettyFormat,
                //全局修改日期格式,如果时间是data、时间戳类型，按照这种格式初始化时间 "yyyy-MM-dd HH:mm:ss"
                SerializerFeature.WriteDateUseDateFormat,
                // 保留map空的字段
                SerializerFeature.WriteMapNullValue,
                // 将String类型的null转成""
                SerializerFeature.WriteNullStringAsEmpty,
                // 将Number类型的null转成0
                SerializerFeature.WriteNullNumberAsZero,
                // 将List类型的null转成[]
                SerializerFeature.WriteNullListAsEmpty,
                // 将Boolean类型的null转成false
                SerializerFeature.WriteNullBooleanAsFalse,
                // 避免循环引用
                SerializerFeature.DisableCircularReferenceDetect);

/* 配置属性拦截 将数字类型转为String传给前台防止数据精度丢失 */
        SerializeConfig serializeConfig = SerializeConfig.globalInstance;
        serializeConfig.put(BigInteger.class, ToStringSerializer.instance);
        serializeConfig.put(Long.class, ToStringSerializer.instance);
        serializeConfig.put(Long.TYPE, ToStringSerializer.instance);
        fastJsonConfig.setSerializeConfig(serializeConfig);

/* 在convert中添加配置信息 */
        converter.setFastJsonConfig(fastJsonConfig);
        return converter;
    }

/**
     * @Author: JiuyeXD
     * @Date: 2022/4/7 11:31
     * @Description: TODO 解决中文乱码
     * @param converters
     */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(responseBodyConverter());
        super.configureMessageConverters(converters);
        /* 定义一个convert转换消息的对象 */
        converters.add(messageConverter());
        /* 追加默认转换器 注:很重要否则不支持其他类型的请求 */
        super.addDefaultHttpMessageConverters(converters);
    }
}
```

Last modification：May 17, 2022