SpringBoot之控制器的返回值处理方式
作者：yyangqqian
这篇文章主要介绍了SpringBoot之控制器的返回值处理方式，具有很好的参考价值，希望对大家有所帮助。如有错误或未考虑完全的地方，望不吝赐教
SpringBoot控制器的返回值处理
@Controller：默认返回值是视图名称，如果需要返回Json字符串，需要在方法上加@ResponseBody注解，默认使用 Jackson 框架处理。@RestController：是@ResponseBody和@Controller的组合注解。
Spring Boot 中默认使用的 Json 解析框架是 Jackson 。
在实际项目中，难免会遇到一些 null 值出现，在转 Json 时，是不希望有这些 null 出现的。
比如期望所有的 null 在转 Json 时都变成 “” 这种空字符串。
在 Spring Boot 中，做一下配置即可，新建一个 Jackson 的配置类：
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;
}
}SpringBoot 启用Fastjson转换
fastJson依赖导入：
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.35</version>
</dependency>SpringBoot 启用Fastjson转换，需要继承WebMvcConfigurerAdapter，并重写configureMessageConverters方法。
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);
}
}SpringBoot控制器返回值-中文乱码问题
@RequestMapping 注解增加produces属性解决中文乱码问题
@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;
}总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。