Spring MVC返回JSON视图的六种方式及对比详解

@Controller
public class UserController {
    @GetMapping("/user/json")
    @ResponseBody
    public User getUser() {
        return new User("John", 30); // 自动序列化为 JSON
    }
}

@RestController
public class UserController {
    @GetMapping("/user/json")
    public User getUser() {
        return new User("John", 30); // 无需 @ResponseBody
    }
}

@RestController
public class UserController {
    @GetMapping("/user/json")
    public ResponseEntity<User> getUser() {
        User user = new User("John", 30);
        return ResponseEntity
            .status(HttpStatus.CREATED)
            .header("X-Custom-Header", "value")
            .body(user);
    }
}

// 定义视图类
class Views {
    static class Public {} 
    static class Internal extends Public {}
}

@RestController
public class UserController {
    @JsonView(Views.Public.class)
    @GetMapping("/user/json/public")
    public User getPublicUser() {
        return new User("John", 30); // 只序列化 @JsonView(Views.Public) 的字段
    }

    @JsonView(Views.Internal.class)
    @GetMapping("/user/json/internal")
    public User getInternalUser() {
        return new User("John", 30); // 序列化 Public 和 Internal 的字段
    }
}

// User 类字段配置
public class User {
    @JsonView(Views.Public.class)
    private String name;
    
    @JsonView(Views.Internal.class)
    private int age;
    // ...
}

@RestController
public class UserController {
    @PostMapping("/user/save")
    public User saveUser(@RequestBody User user) {
        // 反序列化 JSON 请求体到 User 对象
        return user; // 序列化为 JSON 响应
    }
}

@Controller
public class UserController {
    @GetMapping("/user/json")
    public String getUser(Model model) {
        User user = new User("John", 30);
        model.addAttribute("user", user); // 将数据存入模型
        return "jsonView"; // 视图名称
    }
}

@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Bean
    public View jsonView() {
        MappingJackson2JsonView view = new MappingJackson2JsonView();
        view.setExtractValueFromSingleKeyModel(true); // 自动提取模型中的值
        return view;
    }

    @Override
    public void configureViewResolvers(ViewResolverRegistry registry) {
        registry.enableContentNegotiation(); // 启用内容协商
        registry.viewResolver((s, locale) -> jsonView());
    }
}