whitesky's blogjava

 1 @Configuration
 2 public class JsonConfig {
 3 
 4     @Bean
 5     public NumberFormatCustomizer getNumberFormatCustomizer() {
 6         // 配置jackson全局浮點數格式化輸出
 7         return new NumberFormatCustomizer();
 8     }
 9 
10     static class NumberFormatCustomizer implements Jackson2ObjectMapperBuilderCustomizer {
11 
12         @Override
13         public void customize(Jackson2ObjectMapperBuilder jacksonObjectMapperBuilder) {
14             // 配置json序列化
15             // long類型輸出字符串
16             // double和BigDecimal保留兩位小數截斷輸出字符串
17             jacksonObjectMapperBuilder
18                     .serializerByType(Long.class, new StringSerializer())
19                     .serializerByType(Long.TYPE, new StringSerializer())
20                     .serializerByType(Double.class, new NumberSerializer())
21                     .serializerByType(Double.TYPE, new NumberSerializer())
22                     .serializerByType(BigDecimal.class, new NumberSerializer());
23         }
24     }
25 
26     public static class NumberSerializer extends JsonSerializer<Number> {
27 
28         private NumberFormat numberFormat;
29         public NumberSerializer() {
30             this.numberFormat = NumberFormat.getInstance();
31             // 最多兩位小數
32             this.numberFormat.setMaximumFractionDigits(2);
33             // 截斷
34             this.numberFormat.setRoundingMode(RoundingMode.FLOOR);
35         }
36 
37         @Override
38         public void serialize(Number value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
39             if (value != null) {
40                 gen.writeString(this.numberFormat.format(value));
41             }
42         }
43     }
44 }