SpringBoot 配置fastjson 解決js Long類型精度丟失問題

1. 自定義消息轉化器,在@Configuration的類中添加消息轉化器的@bean加入到Spring容器

//此方法位於一個有@Configuration註解的類中
@Bean
public StringHttpMessageConverter stringHttpMessageConverter() {
    StringHttpMessageConverter converter = new StringHttpMessageConverter(Charset.forName("UTF-8"));
    return converter;
}
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或用如下方法

在繼承WebMvcConfigurerAdapter的類中重寫（覆蓋）configureMessageConverters方法

// 自定義消息轉化器的第二種方法
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    StringHttpMessageConverter converter  = new StringHttpMessageConverter(Charset.forName("UTF-8"));
    converters.add(converter);
}
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2.自定義fastjson轉換器：

@Bean
public HttpMessageConverters fastJsonHttpMessageConverters() {
    //1.須要定義一個convert轉換消息的對象;
    FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();
    //2:添加fastJson的配置信息;
    FastJsonConfig fastJsonConfig = new FastJsonConfig();
    fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
    //3處理中文亂碼問題
    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);
    HttpMessageConverter<?> converter = fastJsonHttpMessageConverter;
    return new HttpMessageConverters(converter);

}
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3. 定義一個類，實現ObjectSerializer

import java.io.IOException;
import java.lang.reflect.Type;
import com.alibaba.fastjson.serializer.JSONSerializer;
import com.alibaba.fastjson.serializer.ObjectSerializer;
import com.alibaba.fastjson.serializer.SerializeWriter;
 
public class LongToStringSerializer implements ObjectSerializer {
 
    public static final LongToStringSerializer instance = new LongToStringSerializer();
 
    @Override
    public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType, int features)
        throws IOException {
      SerializeWriter out = serializer.out;
        if (object == null) {
            out.writeNull();
            return;
        }
        String strVal = object.toString();
        out.writeString(strVal);
    }
}
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4. 註解中使用

@JSONField(serializeUsing = LongToStringSerializer.class)
private long id;
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