分布式微服务SpringCloud 、Dubbo常见异常汇总

（1）java.lang.IllegalStateException: RequestParam.value() was empty on parameter 0  

在请求Facade 或是其他 interface时，@RequestParam("phone") String phone，这个参数一定要必填，不可省略。

（2）Consider defining a bean of type 'redis.RedisUtil' 

需要在该项目的启动类中进行全表扫描注入 (basePackages = "com.ballon.wonmore.*")

（3）Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `boolean` out of START_OBJECT token

这种一般是返回值有问题，返回值对不上 或是 多层封装了，程序不能自动识别，比如说 ResultMessage套用ResultMessage

（4）feign.codec.EncodeException: No qualifying bean of type 'org.springframework.boot.autoconfigure.http.HttpMessageConverters' available: expected at least 1 bean which qualifies as autowire candidate.

@RequestMapping(value = "/isInvalidToken", method = RequestMethod.GET, consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
public boolean isInvalidToken(@RequestParam("token") String token) {
return authService.isInvalidToken(token);
}

（5）Caused by: com.netflix.client.ClientException: Load balancer does not have available server for client

（6）feign.codec.DecodeException: No qualifying bean of type 'org.springframework

解决方案：将feignHttpMessageConverter  进行Decoder

@Configuration
public class FeignConfig {

    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }

    @Bean
    public Decoder feignDecoder() {
        return new ResponseEntityDecoder(new SpringDecoder(feignHttpMessageConverter()));
    }

    public ObjectFactory<HttpMessageConverters> feignHttpMessageConverter() {
        final HttpMessageConverters httpMessageConverters = new HttpMessageConverters(new PhpMappingJackson2HttpMessageConverter());
        return new ObjectFactory<HttpMessageConverters>() {
            @Override
            public HttpMessageConverters getObject() throws BeansException {
                return httpMessageConverters;
            }
        };
    }

    public class PhpMappingJackson2HttpMessageConverter extends MappingJackson2HttpMessageConverter {
        PhpMappingJackson2HttpMessageConverter(){
            List<MediaType> mediaTypes = new ArrayList<>();
            mediaTypes.add(MediaType.valueOf(MediaType.TEXT_HTML_VALUE + ";charset=UTF-8")); //关键
            setSupportedMediaTypes(mediaTypes);
        }
    }

}

　　

（7）org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'null' in

这种异常一般来说是因为客户端服务器漏写了注解 比如 @RequestBody 

（8）Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

方案一 (解决原因1)

排除此类的autoconfig。启动以后就可以正常运行。

@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class})

方案二 (解决原因2)

在application.properties/或者application.yml文件中没有添加数据库配置信息.

（9）允许bean 重复定义

spring.main.allow-bean-definition-overriding=true