访问url的时候报500转换错误
我查询出了数据，但是Controll返回值为什么不能是List，其他的String,Date,Int都可以，下面是错误的提示：
No converter found for return value of type: class java.util.ArrayList
6 回答
List转json的时候要配置转换器；增加的配置类继承WebMvcConfigurerAdapter 再重写configureMessageConverters方法 下面是我写得；你试试看！
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
super.configureMessageConverters(converters);
FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
FastJsonConfig fastJsonConfig = new FastJsonConfig();
fastJsonConfig.setSerializerFeatures(
SerializerFeature.WriteNullListAsEmpty,
SerializerFeature.WriteMapNullValue,
SerializerFeature.WriteNullStringAsEmpty
);
fastConverter.setFastJsonConfig(fastJsonConfig);
List<MediaType> supportedMediaTypes = new ArrayList<MediaType>();
supportedMediaTypes.add(MediaType.ALL);
fastConverter.setSupportedMediaTypes(supportedMediaTypes);
converters.add(fastConverter);
}
这个是错误的提示：
2017-11-05 20:19:45.190 ERROR 8632 --- [nio-8000-exec-3] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList] with root cause java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList
其他地方和作者基本都一样的
Controll类：
package com.example.helloboot.Controll; import com.example.helloboot.dao.UserRepository; import com.example.helloboot.entity.User; import com.example.helloboot.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.List;
Repository接口：
package com.example.helloboot.dao; import com.example.helloboot.entity.User; import org.springframework.data.jpa.repository.JpaRepository; import java.util.List;
Service类：
package com.example.helloboot.service; import com.example.helloboot.dao.UserRepository; import com.example.helloboot.entity.User; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List;
导入的包没问题的
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