GraphQL使用
1. 介绍
GraphQL是一个开源的，面向API而创造出来的数据查询操作语言以及相应的运行环境。
GraphQL给客户端自主选择数据内容的能力，客户端完全自主决定获取信息的内容，服务端负责精确的返回目标数据。
我们经常会在某个需求中需要调用多个独立的API接口才能获取到足够的数据，例如客户端要去显示一篇文章的内容，同时也要显示评论、作者信息，那么就可能需要调用文章接口、评论接口、用户接口。这种方式非常的不灵活。另一个case是很多项目都会去拉一些不同的配置文件来决定展示什么，比如我们业务里的app，一打开就有10多个请求，非常不合理，不仅多个请求浪费了带宽，而且速度慢，客户端处理的请求也复杂。
2. graphql-server-demo服务端
2.1 graphql定义文件
player.graphqls
type Player {
id: ID!
name: String!
points: Int!
inventory: [Item!]!
billing: Billing!
}
type Billing {
balance: String! # decimal string...
operations: [Operation!]!
}
type Operation {
amount: String! # decimal string...
description: String
}
type Item {
name: String!
}
type Query {
currentPlayer(id: ID!): Player!
currentPlayerAll: [Player!]!
}
2.2 调用4个独立API接口获取数据
@RequiredArgsConstructor
class Player {
private final Integer id;
private final BillingRepository billingRepository;
private final InventoryClient inventoryClient;
private final PlayerMetadata playerMetadata;
private final PointsCalculator pointsCalculator;
CompletableFuture<Billing> billing() {
return billingRepository.forUser(id);
}
CompletableFuture<String> name() {
return playerMetadata.lookupName(id);
}
CompletableFuture<Integer> points() {
return pointsCalculator.pointsOf(id);
}
CompletableFuture<List<Item>> inventory() {
return inventoryClient.loadInventory(id);
}
}
2.3 API接口实现 - 获取player名称
@Component
@RequiredArgsConstructor
class PlayerMetadata {
private final ExecutorService playerExecutor;
private final Fairy fairy;
CompletableFuture<String> lookupName(Integer playerId) {
return CompletableFuture.supplyAsync(() -> {
Sleeper.sleep(Duration.ofMillis(100));
return fairy.person().getFirstName()+"_id_"+playerId;
}, playerExecutor);
}
}
3. graphql客户端
3.1 currentPlayerAll获取player数据列表
requestBody数据格式
{
currentPlayerAll {
id
name
points
inventory {
name
}
billing {
balance
operations {
amount
description
}
}
}
}
@Log4j2
public class graplql_01 {
private static final String CONTENT_TYPE = "application/graphql";
public static void main(String... args) throws Exception {
String id = invokeRemoteService("currentPlayerAll",11L);
log.info("--------, id = "+id);
// String id2 = invokeRemoteService("currentPlayer",11L);
// log.info("--------, id = "+id2);
}
private static String invokeRemoteService(String methodName, Long traceId) throws Exception {
String url = "http://127.0.0.1:8080/graphql";
// create an instance of RestTemplate
RestTemplate restTemplate = new RestTemplate();
// create headers
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.valueOf(CONTENT_TYPE));// set `content-type` header
// request body parameters
// build the request
String requestBody = null;
if("currentPlayerAll".equals(methodName)){
requestBody = readRequestBody();
}else if("currentPlayer".equals(methodName)){
requestBody = readRequestBodyById();
}
HttpEntity<String> entity = new HttpEntity<>(requestBody, headers);
// send POST request
ResponseEntity<Object> response = restTemplate.postForEntity(url, entity, Object.class);
// check response
if (response.getStatusCode() == HttpStatus.CREATED || response.getStatusCode() == HttpStatus.OK) {
log.info("Request [" + traceId + "] Successful 200 content = \n" + JSON.toJSONString(response.getBody(),true));
JSONObject jsonObject = JSON.parseObject(JSON.toJSONString(response.getBody()));
JSONObject data = jsonObject.getJSONObject("data");
String ids = "";
if("currentPlayerAll".equals(methodName)){
JSONArray currentPlayers = data.getJSONArray(methodName);
/**获取id列表**/
List<String> playerIds = Arrays.stream(currentPlayers.toArray()).map(f -> ((JSONObject)f).getString("id")).collect(Collectors.toList());
String playerIdsStr = playerIds.stream().collect(Collectors.joining("::"));
ids = playerIdsStr;
}else if("currentPlayer".equals(methodName)){
JSONObject currentPlayer = data.getJSONObject(methodName);
ids = currentPlayer.getString("id");
}
return ids;
} else {
log.info("Request [" + traceId + "] Failed [" + response.getStatusCode() + "] content = " + response.getBody());
return "-1";
}
}
private static String readRequestBody() throws URISyntaxException, IOException {
Stream<String> lines = Files.lines(
Paths.get(ClassLoader.getSystemResource("request_body.txt").toURI()));
return lines.collect(Collectors.joining());
}
private static String readRequestBodyById() throws URISyntaxException, IOException {
Stream<String> lines = Files.lines(
Paths.get(ClassLoader.getSystemResource("request_body2.txt").toURI()));
return lines.collect(Collectors.joining());
}
}
调用结果:
{
"data":{
"currentPlayerAll":[
{
"id":"1315563916",
"name":"Nicholas_id_1315563916",
"points":42,
"inventory":[
{
"name":"Sword"
},
{
"name":"Sword"
}
],
"billing":{
"balance":"10",
"operations":[
{
"amount":"10",
"description":"Item purchase"
},
{
"amount":"1",
"description":"Item purchase"
}
]
}
},
{
"id":"269998305",
"name":"Luke_id_269998305",
"points":42,
"inventory":[
{
"name":"Shoes"
},
{
"name":"Shoes"
}
],
"billing":{
"balance":"10",
"operations":[
{
"amount":"10",
"description":"Item purchase"
},
{
"amount":"1",
"description":"Item purchase"
}
]
}
}
]
}
}
3.2 currentPlayer获取某个ID对应的player数据
requestBody数据格式
{
currentPlayer(id: 11) {
id
name
points
inventory {
name
}
billing {
balance
operations {
amount
description
}
}
}
}
调用结果：
{
"data":{
"currentPlayer":{
"id":"11",
"name":"Aaron_id_11",
"points":42,
"inventory":[
{
"name":"Potion"
},
{
"name":"Shoes"
}
],
"billing":{
"balance":"10",
"operations":[
{
"amount":"10",
"description":"Item purchase"
},
{
"amount":"1",
"description":"Item purchase"
}
]
}
}
}
}
3.3 currentPlayer获取不同格式的player数据
requestBody数据格式
{
currentPlayer(id: 11) {
id
name
points
billing {
balance
operations {
amount
}
}
}
}
调用结果：
{
"data":{
"currentPlayer":{
"id":"11",
"name":"Allison_id_11",
"points":42,
"billing":{
"balance":"10",
"operations":[
{
"amount":"10"
},
{
"amount":"1"
}
]
}
}
}
}
标签：String,private,id,amount,GraphQL,使用,currentPlayer,name From： https://www.cnblogs.com/sanqianyuejia/p/17010923.html