feat: 任务开始页面，相关逻辑补充

src/main/java/com/guo/learningprogresstracker/config/JacksonConfig.java

@@ -1,10 +1,12 @@
 package com.guo.learningprogresstracker.config;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.module.SimpleModule;
 import com.guo.learningprogresstracker.config.serializer.LocalDateTimeSerializer;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 
 import java.time.LocalDateTime;
 
@@ -14,11 +16,17 @@ import java.time.LocalDateTime;
 @Configuration
 public class JacksonConfig {
     @Bean
-    public ObjectMapper objectMapper() {
-        ObjectMapper mapper = new ObjectMapper();
+    public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder) {
+        ObjectMapper mapper = builder.build();
+
+        // 注册自定义序列化器
         SimpleModule module = new SimpleModule();
         module.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());
         mapper.registerModule(module);
+
+        // 关闭序列化为时间戳（使用字符串格式）
+        mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
+
         return mapper;
     }
 }

src/main/java/com/guo/learningprogresstracker/config/serializer/LocalDateTimeSerializer.java

@@ -10,8 +10,8 @@ import java.time.format.DateTimeFormatter;
 
 public class LocalDateTimeSerializer extends StdSerializer<LocalDateTime> {
 
-    // 定义你希望使用的日期时间格式
-    private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");;
+    // 修改为ISO 8601格式，末尾带Z，表示UTC时区
+    private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");
 
     public LocalDateTimeSerializer() {
         super(LocalDateTime.class);
@@ -22,9 +22,8 @@ public class LocalDateTimeSerializer extends StdSerializer<LocalDateTime> {
         if (value == null) {
             gen.writeNull();
         } else {
-            // 格式化LocalDateTime为字符串
+            // 这里假设LocalDateTime是UTC时间，直接格式化并加Z
             String formattedDate = value.format(formatter);
-            // 将格式化后的字符串写入JSON流作为一个值
             gen.writeString(formattedDate);
         }
     }