在springboot里,推荐我们通过 WebMvcConfigurer
的派生类重写你的请求,你可以利用WebMvcConfigurer对http请求添加一些拦截器,addCorsMappings,addResourceHandlers,消息返回格式等等,需要注意的是,你需要使用 @EnableWebMvc
注解override springboot默认的方法;WebMvcConfigurer虽然是接口,但它的方法都是有default默认实现的。
public interface WebMvcConfigurer { default void configurePathMatch(PathMatchConfigurer configurer) { } default void configureContentNegotiation(ContentNegotiationConfigurer configurer) { } default void configureAsyncSupport(AsyncSupportConfigurer configurer) { } ... }
我们来定义自己的WebMvcConfigurer,并且重写一个JSON输出的格式
@Configuration @EnableWebMvc //覆盖默认的配置 public class WebMvcConfigurerImpl implements WebMvcConfigurer { @Override public void configureMessageConverters(List<HttpMessageConverter<?>> converters) { MappingJackson2HttpMessageConverter jackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter(); ObjectMapper objectMapper = new ObjectMapper(); /** * 序列换成Json时,将所有的Long变成String * 因为js中得数字类型不能包括所有的java Long值 */ SimpleModule simpleModule = new SimpleModule(); simpleModule.addSerializer(Long.class, ToStringSerializer.instance); simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance); // 所有的double类型返回保留三位小数 simpleModule.addSerializer(BigDecimal.class, new MoneySerialize()); // double保留两位小数 simpleModule.addSerializer(Double.class, new DoubleSerialize()); simpleModule.addSerializer(Double.TYPE, new DoubleSerialize()); objectMapper.registerModule(simpleModule); jackson2HttpMessageConverter.setObjectMapper(objectMapper); converters.add(jackson2HttpMessageConverter); } /** * money serializer. */ public class MoneySerialize extends JsonSerializer<Object> { //修改要除的数据 final BigDecimal TEMP = BigDecimal.valueOf(1000000L); @Override public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException { if (value != null) { BigDecimal bigDecimal = new BigDecimal(value.toString()); gen.writeNumber(bigDecimal.divide(TEMP, 4, RoundingMode.DOWN)); } } } /** * double serializer. */ public class DoubleSerialize extends JsonSerializer<Double> { private DecimalFormat df = new DecimalFormat("##.00"); @Override public void serialize(Double value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException { if (value != null) { gen.writeString(df.format(value)); } } }
然后我们在返回对象之后,它的double,BigDecimal的属性将被格式化
{"name":"zzl","email":null,"sex":null,"total":"5.00","totalMoney":0.0001}