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
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{ "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
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{ "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
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<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
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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 */@Configurationpublic 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; }} |
添加空值統一處理后的返回值
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{ "flag": true, "code": "10000", "msg": "成功！", "data": { "id": 32, "templateType": 1, "templateName": "", "freightName": "", "listArea": [], "templateDescEntity": {} }} |
到此這篇關于springboot配置Jackson返回統一默認值的實現示例的文章就介紹到這了,更多相關springboot Jackson返回統一默認值內容請搜索服務器之家以前的文章或繼續瀏覽下面的相關文章希望大家以后多多支持服務器之家！
原文鏈接：https://juejin.cn/post/6989848776361902088
