我刚刚阅读了 Spring 4.1 中一些非常棒的特性，它们允许您通过注释使用不同的视图。
来自：https://spring.io/blog/2014/12/02/latest-jackson-integration-improvements-in-spring
public class View {
interface Summary {}
}
public class User {
@JsonView(View.Summary.class)
private Long id;
@JsonView(View.Summary.class)
private String firstname;
@JsonView(View.Summary.class)
private String lastname;
private String email;
private String address;
private String postalCode;
private String city;
private String country;
}
public class Message {
@JsonView(View.Summary.class)
private Long id;
@JsonView(View.Summary.class)
private LocalDate created;
@JsonView(View.Summary.class)
private String title;
@JsonView(View.Summary.class)
private User author;
private List<User> recipients;
private String body;
}
感谢 Spring MVC @JsonView 支持，可以根据每个处理程序方法选择应该序列化的字段：
@RestController
public class MessageController {
@Autowired
private MessageService messageService;
@JsonView(View.Summary.class)
@RequestMapping("/")
public List<Message> getAllMessages() {
return messageService.getAll();
}
@RequestMapping("/{id}")
public Message getMessage(@PathVariable Long id) {
return messageService.get(id);
}
}
在此示例中，如果检索到所有消息，则只有最重要的字段会被序列化，这要归功于带有 @JsonView(View.Summary.class) 注释的 getAllMessages() 方法：
[ {
"id" : 1,
"created" : "2014-11-14",
"title" : "Info",
"author" : {
"id" : 1,
"firstname" : "Brian",
"lastname" : "Clozel"
}
}, {
"id" : 2,
"created" : "2014-11-14",
"title" : "Warning",
"author" : {
"id" : 2,
"firstname" : "Stéphane",
"lastname" : "Nicoll"
}
}, {
"id" : 3,
"created" : "2014-11-14",
"title" : "Alert",
"author" : {
"id" : 3,
"firstname" : "Rossen",
"lastname" : "Stoyanchev"
}
} ]
在 Spring MVC 默认配置中，MapperFeature.DEFAULT_VIEW_INCLUSION 设置为 false。这意味着当启用 JSON 视图时，非注释字段或属性（如正文或收件人）不会被序列化。
当使用 getMessage() 处理程序方法（未指定 JSON 视图）检索特定消息时，所有字段都按预期序列化：
{
"id" : 1,
"created" : "2014-11-14",
"title" : "Info",
"body" : "This is an information message",
"author" : {
"id" : 1,
"firstname" : "Brian",
"lastname" : "Clozel",
"email" : "bclozel@pivotal.io",
"address" : "1 Jaures street",
"postalCode" : "69003",
"city" : "Lyon",
"country" : "France"
},
"recipients" : [ {
"id" : 2,
"firstname" : "Stéphane",
"lastname" : "Nicoll",
"email" : "snicoll@pivotal.io",
"address" : "42 Obama street",
"postalCode" : "1000",
"city" : "Brussel",
"country" : "Belgium"
}, {
"id" : 3,
"firstname" : "Rossen",
"lastname" : "Stoyanchev",
"email" : "rstoyanchev@pivotal.io",
"address" : "3 Warren street",
"postalCode" : "10011",
"city" : "New York",
"country" : "USA"
} ]
}
@JsonView 注解只能指定一个类或接口，但您可以使用继承来表示 JSON 视图层次结构（如果字段是 JSON 视图的一部分，它也将是父视图的一部分）。例如，此处理程序方法将序列化带有@JsonView(View.Summary.class) 和@JsonView(View.SummaryWithRecipients.class) 注释的字段：
public class View {
interface Summary {}
interface SummaryWithRecipients extends Summary {}
}
public class Message {
@JsonView(View.Summary.class)
private Long id;
@JsonView(View.Summary.class)
private LocalDate created;
@JsonView(View.Summary.class)
private String title;
@JsonView(View.Summary.class)
private User author;
@JsonView(View.SummaryWithRecipients.class)
private List<User> recipients;
private String body;
}
@RestController
public class MessageController {
@Autowired
private MessageService messageService;
@JsonView(View.SummaryWithRecipients.class)
@RequestMapping("/with-recipients")
public List<Message> getAllMessagesWithRecipients() {
return messageService.getAll();
}
}