自定义null值序列化处理器、配置jackson实体

yxt-common/yxt-common-base/src/main/java/com/yxt/common/base/config/CustomizeNullJsonSerializer.java

@@ -0,0 +1,72 @@
+package com.yxt.common.base.config;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+
+import java.io.IOException;
+
+/**
+ * @Author dimengzhe
+ * @Date 2022/4/29 18:59
+ * @Description
+ */
+public class CustomizeNullJsonSerializer {
+
+    /**
+     * 处理数组集合类型的null值
+     */
+    public static class NullArrayJsonSerializer extends JsonSerializer<Object> {
+        @Override
+        public void serialize(Object value, JsonGenerator jsonGenerator,
+                              SerializerProvider serializerProvider) throws IOException {
+            jsonGenerator.writeStartArray();
+            jsonGenerator.writeEndArray();
+        }
+    }
+
+    /**
+     * 处理字符串类型的null值
+     */
+    public static class NullStringJsonSerializer extends JsonSerializer<Object> {
+        @Override
+        public void serialize(Object value, JsonGenerator jsonGenerator,
+                              SerializerProvider serializerProvider) throws IOException {
+            jsonGenerator.writeString("");
+        }
+    }
+
+    /**
+     * 处理数值类型的null值
+     */
+    public static class NullNumberJsonSerializer extends JsonSerializer<Object> {
+        @Override
+        public void serialize(Object value, JsonGenerator jsonGenerator,
+                              SerializerProvider serializerProvider) throws IOException {
+            jsonGenerator.writeNumber(0);
+        }
+    }
+
+    /**
+     * 处理boolean类型的null值
+     */
+    public static class NullBooleanJsonSerializer extends JsonSerializer<Object> {
+        @Override
+        public void serialize(Object value, JsonGenerator jsonGenerator,
+                              SerializerProvider serializerProvider) throws IOException {
+            jsonGenerator.writeBoolean(false);
+        }
+    }
+
+    /**
+     * 处理实体对象类型的null值
+     */
+   /* public static class NullObjectJsonSerializer extends JsonSerializer<Object> {
+        @Override
+        public void serialize(Object value, JsonGenerator jsonGenerator,
+                              SerializerProvider serializerProvider) throws IOException {
+            jsonGenerator.writeStartObject();
+            jsonGenerator.writeEndObject();
+        }
+    }*/
+}

yxt-common/yxt-common-base/src/main/java/com/yxt/common/base/config/JacksonConfig.java

@@ -25,10 +25,6 @@
  *********************************************************/
 package com.yxt.common.base.config;
 
-import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.core.JsonProcessingException;
-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;
@@ -37,8 +33,6 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 
-import java.io.IOException;
-
 /**
  * Project: yxt-common <br/>
  * File: JacksonConfig.java <br/>
@@ -54,7 +48,7 @@ import java.io.IOException;
  */
 @Configuration
 public class JacksonConfig {
-    @Bean
+  /*  @Bean
     @Primary
     @ConditionalOnMissingBean(ObjectMapper.class)
     public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
@@ -68,6 +62,21 @@ public class JacksonConfig {
             }
         });
         return objectMapper;
+    }*/
+
+    @Bean
+    @Primary
+    @ConditionalOnMissingBean(ObjectMapper.class)
+    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
+        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
+        /** 为objectMapper注册一个带有SerializerModifier的Factory */
+        objectMapper.setSerializerFactory(objectMapper.getSerializerFactory()
+                .withSerializerModifier(new MyBeanSerializerModifier()));
+
+        SerializerProvider serializerProvider = objectMapper.getSerializerProvider();
+//        serializerProvider.setNullValueSerializer(new CustomizeNullJsonSerializer
+//                .NullObjectJsonSerializer());
+        return objectMapper;
     }
 
 }

yxt-common/yxt-common-base/src/main/java/com/yxt/common/base/config/MyBeanSerializerModifier.java

@@ -0,0 +1,68 @@
+package com.yxt.common.base.config;
+
+import com.fasterxml.jackson.databind.BeanDescription;
+import com.fasterxml.jackson.databind.SerializationConfig;
+import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;
+import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;
+
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * @Author dimengzhe
+ * @Date 2022/4/29 18:58
+ * @Description
+ */
+public class MyBeanSerializerModifier extends BeanSerializerModifier {
+
+    @Override
+    public List<BeanPropertyWriter> changeProperties(SerializationConfig config,
+                                                     BeanDescription beanDesc,
+                                                     List<BeanPropertyWriter> beanProperties) {
+        // 循环所有的beanPropertyWriter
+        for (int i = 0; i < beanProperties.size(); i++) {
+            BeanPropertyWriter writer = beanProperties.get(i);
+            // 判断字段的类型，如果是数组或集合则注册nullSerializer
+           /* if (isArrayType(writer)) {
+                // 给writer注册一个自己的nullSerializer
+                writer.assignNullSerializer(new CustomizeNullJsonSerializer.NullArrayJsonSerializer());
+            }*/
+            if (isStringType(writer)) {
+                writer.assignNullSerializer(new CustomizeNullJsonSerializer.NullStringJsonSerializer());
+            }
+        }
+        return beanProperties;
+    }
+
+    /**
+     * 是否是数组
+     */
+    private boolean isArrayType(BeanPropertyWriter writer) {
+        Class<?> clazz = writer.getType().getRawClass();
+        return clazz.isArray() || Collection.class.isAssignableFrom(clazz);
+    }
+
+    /**
+     * 是否是String
+     */
+    private boolean isStringType(BeanPropertyWriter writer) {
+        Class<?> clazz = writer.getType().getRawClass();
+        return CharSequence.class.isAssignableFrom(clazz) || Character.class.isAssignableFrom(clazz);
+    }
+
+    /**
+     * 是否是数值类型
+     */
+    private boolean isNumberType(BeanPropertyWriter writer) {
+        Class<?> clazz = writer.getType().getRawClass();
+        return Number.class.isAssignableFrom(clazz);
+    }
+
+    /**
+     * 是否是boolean
+     */
+    private boolean isBooleanType(BeanPropertyWriter writer) {
+        Class<?> clazz = writer.getType().getRawClass();
+        return clazz.equals(Boolean.class);
+    }
+}