springboot配置Jackson返回統一默認值的實現示例
在項目開發中,我們返回的數據或者對象沒有的時候一般直接返回的null
有數據時的返回值
{ "flag": true, "code": "10000", "msg": "成功!", "data": { "id": 32, "templateType": 1, "templateName": "我的測試模板1", "freightName": "我的測試標題1", "listArea": [ { "id": 968, "templateId": 32, "freightPrice": 15, } ], "templateDescEntity": { "id": 1 "name": "xxx" } } }
沒有數據時的返回值
{ "flag": true, "code": "10000", "msg": "成功!", "data": { "id": 32, "templateType": 1, "templateName": null, "freightName": null, "listArea": null, "templateDescEntity": null } }
這種情況下數據返回給前端,前端需要做大量的空值判斷
如前端調使用屬性data.templateDescEntity.id的時候就會直接報異常
此時我們可以使用返回值統一處理,配置如下
pom.xml添加
<dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>2.9.5</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> </dependency>
java類添加配置
package com.ys.mall.core.product.config; 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; import java.lang.reflect.Field; import java.util.Collection; import java.util.List; import java.util.Map; import java.util.Objects; /** * 數據返回給前端時,設置null值默認為"" * * @author cgh * @date 2020/12/14 10:35 */ @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 { String fieldName = jsonGenerator.getOutputContext().getCurrentName(); try { //反射獲取字段類型 Field field = jsonGenerator.getCurrentValue().getClass().getDeclaredField(fieldName); if (CharSequence.class.isAssignableFrom(field.getType())) { //字符串型空值"" jsonGenerator.writeString(""); return; } else if (Collection.class.isAssignableFrom(field.getType())) { //列表型空值返回[] jsonGenerator.writeStartArray(); jsonGenerator.writeEndArray(); return; } else if (Map.class.isAssignableFrom(field.getType())) { //map型空值 或者 bean對象 返回{} jsonGenerator.writeStartObject(); jsonGenerator.writeEndObject(); return; } } catch (NoSuchFieldException ignored) { } jsonGenerator.writeString(""); } }); return objectMapper; } }
添加空值統一處理後的返回值
{ "flag": true, "code": "10000", "msg": "成功!", "data": { "id": 32, "templateType": 1, "templateName": "", "freightName": "", "listArea": [], "templateDescEntity": {} } }
到此這篇關於springboot配置Jackson返回統一默認值的實現示例的文章就介紹到這瞭,更多相關springboot Jackson返回統一默認值內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet!
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