使用Jackson3反序列化PagedModel遇IllegalAccessError，如何保留AfterBurnerModule修复？

问题场景 #

使用依赖：

• jackson-module-afterburner (3.0.4)
• spring-hateoas (3.0.2)

执行以下代码将HATEOAS JSON反序列化为org.springframework.hateoas.PagedModel时，触发IllegalAccessError：

JsonMapper.builder()
          .addModule(new AfterburnerModule())
          .addModule(new HalJacksonModule())
          .build()
          .readValue("""
            {
              "_embedded": {
                "dtoList": [{"id": 21}]
              },
              "_links": {
                "self": {"href": "http://localhost:8080/api/dtos?page=0&size=20"}
              },
              "page": {
                "number": 0,
                "size": 20,
                "totalElements": 1,
                "totalPages": 1
              }
            }""", PagedModel.class)

异常日志：

java.lang.IllegalAccessError: class org.springframework.hateoas.PagedModel$Creator4JacksonDeserializere4fb0aac tried to access protected method 'void org.springframework.hateoas.PagedModel.<init>()' (org.springframework.hateoas.PagedModel$Creator4JacksonDeserializere4fb0aac is in unnamed module of loader tools.jackson.module.afterburner.util.MyClassLoader @55f3c410; org.springframework.hateoas.PagedModel is in unnamed module of loader 'app')

    at org.springframework.hateoas.PagedModel$Creator4JacksonDeserializere4fb0aac.createUsingDefault(Unknown Source)
    at tools.jackson.module.afterburner.deser.SuperSonicUnrolledDeserializer.deserializeFromObject(SuperSonicUnrolledDeserializer.java:369)
    at tools.jackson.databind.deser.bean.BeanDeserializer.deserialize(BeanDeserializer.java:200)
    at tools.jackson.module.afterburner.deser.SuperSonicUnrolledDeserializer.deserialize(SuperSonicUnrolledDeserializer.java:150)
    at tools.jackson.databind.deser.DeserializationContextExt.readRootValue(DeserializationContextExt.java:265)
    at tools.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2611)
    at tools.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:1518)

问题核心：Afterburner模块用自定义类加载器生成的反序列化类，尝试访问PagedModel的无参保护构造方法，但类加载器隔离导致权限校验失败。

无需移除AfterburnerModule的修复方案 #

方案1：让Afterburner跳过PagedModel的优化 #

通过Afterburner模块的配置，排除PagedModel或整个Spring HATEOAS模型包使用优化逻辑，改用Jackson默认反序列化：

JsonMapper mapper = JsonMapper.builder()
        .addModule(new AfterburnerModule()
                // 排除单个类
                .addDeserializationExclusion(PagedModel.class)
                // 可选：排除整个Spring HATEOAS模型包，避免后续其他类出问题
                .addDeserializationExclusion("org.springframework.hateoas")
                .setUseValueClassLoader(false))
        .addModule(new HalJacksonModule())
        .build();

方案2：基于Spring HATEOAS预配置Mapper扩展 #

Spring HATEOAS自带适配Hal格式的ObjectMapper配置，在此基础上添加Afterburner并排除目标类：

// 初始化Spring HATEOAS适配的Mapper
ObjectMapper hateoasMapper = new ObjectMapper();
hateoasMapper.registerModule(new Jackson2HalModule());

// 添加Afterburner并排除PagedModel优化
AfterburnerModule afterburnerModule = new AfterburnerModule();
afterburnerModule.addDeserializationExclusion(PagedModel.class);
hateoasMapper.registerModule(afterburnerModule);

// 执行反序列化
PagedModel<?> result = hateoasMapper.readValue(jsonString, PagedModel.class);

方案3：Java 9+模块化项目开放权限 #

如果是模块化项目，在module-info.java中给Afterburner模块开放PagedModel的构造方法访问权限：

module your.app.module {
    opens org.springframework.hateoas to tools.jackson.module.afterburner;
}

内容的提问来源于stack exchange，提问作者wintenbb