java - 如何更改 Json 格式?
问题描述
我想更改显示 Json 的格式。
我试图打印整个 Item 对象,它正在打印所有属性(看起来很正常)。我尝试更改控制器和服务以返回 String,并尝试操作 String,但我认为这不是解决问题的好方法。一定是更好的东西。
{
"requestedUrl":"https://www.googleapis.com/books/v1/volumes?q=java&maxResults=40",
"items":[
{
"id":"-SYM4PW-YAgC",
"volumeInfo":{
"title":"The Religion of Java",
"authors":[
"Clifford Geertz"
],
"industryIdentifiers":[
{
"type":"ISBN_10",
"identifier":"0226285103"
},
{
"type":"ISBN_13",
"identifier":"9780226285108"
}
],
"readingModes":{
"text":true,
"image":true
},
"pageCount":392,
"printType":"BOOK",
"categories":[
"Religion"
]
}
}
]
}
BookController.java
@CrossOrigin
@RestController
@RequestMapping("/")
public class BookController {
private BookService service;
public BookController(BookService service) {
this.service = service;
}
@GetMapping("book/{isbn}")
public Item getBook(@PathVariable String isbn) {
return service.findBookByISBN(isbn);
}
}
图书服务.java
public class BookService {
public BookService() throws IOException {
}
public Item findBookByISBN(String isbn) {
// listOfItems taking json file from json file and making List<Item> to itarate over
for (Item item : listOfItems) {
if (item.getVolumeInfo().getIndustryIdentifiers().get(0).getIdentifier().equals(isbn)) {
return item;
}
}
return null;
}
}
当然,我有 POJO 课......
对于findBookByISBN(9780226285108)
json answear 是
{
"title":"The Religion of Java",
"authors":[
"Clifford Geertz"
],
"industryIdentifiers":[
{
"type":"ISBN_10",
"identifier":"0226285103"
},
{
"type":"ISBN_13",
"identifier":"9780226285108"
}
],
"readingModes":{
"text":true,
"image":true
},
"pageCount":392,
"printType":"BOOK",
"categories":[
"Religion"
]
}
但我想让我的 json 像这样:
{
"title":"The Religion of Java",
"printType":"BOOK",
"pageCount":392,
"authors":[
"Clifford Geertz"
],
"categories":[
"Religion"
]
}
解决方案
您可以使用数据传输对象 (DTO) 并仅发送所需的信息作为响应。
{
"title":"The Religion of Java",
"printType":"BOOK",
"pageCount":392,
"authors":[
"Clifford Geertz"
],
"categories":[
"Religion"
]
}
在这种情况下,您可以编写一个 DTO,例如
class NameYouWant{
String title;
String printType;
Integer pageCount;
List<String> authors = new ArrayList<>();
List<String> categories = new ArrayList<>();
//generate getters and setters of the above data members.
}
现在,当您发送响应时,在此 dto 中设置数据,如下所示:- 创建对象
public Item findBookByISBN(String isbn) {
for (Item item : listOfItems) {
if (item.getVolumeInfo().getIndustryIdentifiers().get(0).getIdentifier().equals(isbn)) {
NameYouWant na = new NameYouWant();
na.setTitle(item.getTitle());
na.setPrintType(item.getPrintType());
na.setPageCount(item.getPageCount());
na.SetAuthors(item.getAuthors());
na.SetCategories(item.getCategories());
return na;
}
}
return null;
}
通过这种方式,您可以只在 forntend 中发送所需的数据。