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在实际的开发过程中，经常会遇到后台需要返回给前端的JSON数据中包含不必要属性的问题。为了实现对返回数据的精确控制，可以通过自定义注解和Spring的消息转换器来实现字段过滤。以下是具体实现方法和优化思路。

整体思路

实现步骤

1. 定义自定义注解

@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)public @interface SerializeField {    Class
    clazz();    String[] includes() default {};    String[] excludes() default {};}

2. 实现ResponseBodyAdvice

@ControllerAdvicepublic class JsonFilterResponseBodyAdvice implements ResponseBodyAdvice {    @Override    public Object beforeBodyWrite(Object object, MethodParameter methodParameter, MediaType mediaType,                                Class
   > converterType, ServerHttpRequest serverHttpRequest,                                ServerHttpResponse serverHttpResponse) {        if (methodParameter.getMethod().isAnnotationPresent(SerializeField.class)) {            JsonFilterObject jsonFilterObject = new JsonFilterObject();            handleAnnotation(methodParameter.getMethod().getAnnotation(SerializeField.class), jsonFilterObject);            jsonFilterObject.setObject(object);            return jsonFilterObject;        }        return object;    }    private void handleAnnotation(SerializeField serializeField, JsonFilterObject jsonFilterObject) {        // 提取注解参数进行处理        // 具体实现逻辑可根据需求扩展    }}

3. 实现自定义消息转换器

public class JsonFilterHttpMessageConverter extends FastJsonHttpMessageConverter {    // 其他配置可参考FastJsonHttpMessageConverter的实现    @Override    protected void writeInternal(Object obj, HttpOutputMessage outputMessage) throws IOException {        if (obj instanceof JsonFilterObject) {            JsonFilterObject jsonFilterObject = (JsonFilterObject) obj;            // 使用SimpleSerializerFilter进行字段过滤            String text = JSON.toJSONString(jsonFilterObject.getObject(), new SimpleSerializerFilter(                jsonFilterObject.getIncludes(), jsonFilterObject.getExcludes()            ), this.features);            OutputStream out = outputMessage.getBody();            out.write(text.getBytes(this.charset));        } else {            // 未声明注解直接序列化            OutputStream out = outputMessage.getBody();            String text = JSON.toJSONString(obj, this.features);            out.write(text.getBytes(this.charset));        }    }}

使用示例

1. 控制层

@RestControllerpublic class DemoController {    @GetMapping("user")    @SerializeField(clazz = User.class, includes = {"name", "id"})    public User getUser() {        User user = new User(1L, "jjc", "123456");        return user;    }}

2. 返回结果示例

{    "id": 1,    "name": "jjc"}

3. 复杂对象处理

@GetMapping("userMulti")@MultiSerializeField(clazz = User.class, includes = {"name", "id", "addresses"})public User getUserMulti() {    User user = new User(1L, "jjc", "123456");    List
 addresses = new ArrayList<>();    addresses.add(new Address("liuyis's home", "liuyis's school", user));    addresses.add(new Address("liuyis's home2", "liuyis's school2", user));    user.setAddresses(addresses);    return user;}

4. 返回结果

{    "addresses": [        {            "home": "liuyis's home",            "school": "liuyis's school"        },        {            "home": "liuyis's home2",            "school": "liuyis's school2"        }    ],    "id": 1,    "name": "jjc"}

优化与扩展

通过以上方法，开发者可以灵活控制JSON数据的输出格式，显著提升前端数据处理的效率和用户体验。