SpringBoot之控制器的返回值处理方式

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
import java.io.IOException;
@Configuration
public class JacksonConfig {
    @Bean
    @Primary
    @ConditionalOnMissingBean(ObjectMapper.class)
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
                jsonGenerator.writeString("");
            }
        });
        return objectMapper;
    }
}

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.35</version>
</dependency>

import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
@Configuration
public class FastJWebMvcConfigurer extends WebMvcConfigurationSupport {
    /***
     * 使用阿里 FastJson 作为JSON MessageConverter
     * @param converters
     * */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
        FastJsonConfig config = new FastJsonConfig();
        config.setSerializerFeatures(
                // 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);
        // converter.setFastJsonConfig(config);
        converter.setDefaultCharset(Charset.forName("UTF-8"));
        List<MediaType> mediaTypeList = new ArrayList<>();
        // 解决中文乱码问题，相当于在Controller上的@RequestMapping中加了个属性produces = "application/json"
        mediaTypeList.add(MediaType.APPLICATION_JSON);
        converter.setSupportedMediaTypes(mediaTypeList);
        converters.add(converter);
    }
}

@RequestMapping(value="/create/index",produces = "application/json;charset=utf-8")
public ResponseBean createIndex(@RequestParam String indexName)
        {
        try {
        XContentBuilder builder = XContentFactory.jsonBuilder()
        .startObject()
        .field("properties")
        .startObject()
        .field("name").startObject().field("index", "true").field("type", "keyword").endObject()
        .field("age").startObject().field("index", "true").field("type", "integer").endObject()
        .field("money").startObject().field("index", "true").field("type", "double").endObject()
        .field("address").startObject().field("index", "true").field("type", "text").endObject()
        .field("birthday").startObject().field("index", "true").field("type", "date").endObject()
//.field("address").startObject().field("index", "true").field("type", "text").field("analyzer", "ik_max_word").endObject()
//.field("birthday").startObject().field("index", "true").field("type", "date").field("format", "strict_date_optional_time||epoch_millis").endObject()
        .endObject()
        .endObject();
        CreateIndexRequest createIndexRequest = new CreateIndexRequest(indexName);
        createIndexRequest.mapping(indexName,builder);
        CreateIndexResponse createIndexResponse = client.indices().create(createIndexRequest, RequestOptions.DEFAULT);
        boolean acknowledged = createIndexResponse.isAcknowledged();
        if (acknowledged) {
        return new ResponseBean(200, "创建成功", null);
        } else {
        return new ResponseBean(1002, "创建失败", null);
        }
        } catch (IOException e) {
        e.printStackTrace();
        }catch (ElasticsearchStatusException e)
        {
        logger.info("创建失败---索引已经存在");
        return new ResponseBean(1002, "创建失败---索引已经存在", null);
        }
        return null;
        }