Java对接GraphQL
GraphQL的逻辑如果在java实现感觉还是很复杂，因为其相当于一种组排的策略模式。好在不需要进行相应的实现，只需要调用别人的接口即可。
但java调用GraphQL接口的成熟客户端好像就只有一个，当我们去maven中央仓库寻找客户端依赖时发现好像就只有这一个客户端
进入该依赖库发现GitHub地址：GitHub - graphql-java/graphql-java: GraphQL Java implementation
我们找到官方文档，可以看到结构确实复杂，学习成本很高。
所以没必要浪费太多时间。我随后找到了私人开源作品：
pom:
<!-- https://mvnrepository.com/artifact/org.mountcloud/graphql-client -->
<dependency>
<groupId>org.mountcloud</groupId>
<artifactId>graphql-client</artifactId>
<version>1.2</version>
</dependency> |
同理 我们去maven仓库寻找GitHub开源地址：GitHub - MountCloud/graphql-client: graphql client for java
发现给的例子很少但是简洁明了也符合我们需求。
所以，java对GraphQL的请求都模仿自这里，我直接把文档的内容搬过来然后做个对比：
do query
//crate client
GraphqlClient client = GraphqlClient.buildGraphqlClient("http://localhost:8081/graphql");
//create http headers
Map<String,String> headers = new HashMap<String,String>();
headers.put("token","123");
client.setHttpHeaders(headers);
//create query
GraphqlQuery query = new DefaultGraphqlQuery("findUsers");
//add query or mutation param
query.addParameter("sex","man").addParameter("age",11);
//add query response basics attribute
query.addResultAttributes("id","name","age","sex");
//add query complex attributes
ResultAttributtes classAttributte = new ResultAttributtes("class");
classAttributte.addResultAttributes("name","code");
//attributes can be more complex
ResultAttributtes schoolAttributte = new ResultAttributtes("school");
schoolAttributte.addResultAttributes("name");
//class add school attribute
classAttributte.addResultAttributes(schoolAttributte);
//do query
try {
GraphqlResponse response = client.doQuery(query);
//this map is graphql result
Map data = response.getData();
} catch (IOException e) {
e.printStackTrace();
}
query is
query{
findUsers(sex:"man",age:11){
id
name
age
sex
class{
name
code
school{
name
}
}
}
}
|
do mutation
//crate client
GraphqlClient client = GraphqlClient.buildGraphqlClient("http://localhost:8081/graphql");
//create http headers
Map<String,String> headers = new HashMap<String,String>();
headers.put("token","123");
client.setHttpHeaders(headers);
//create mutaion
GraphqlMutation mutation = new DefaultGraphqlMutation("updateUser");
//create param
mutation.addParameter("id",1).addParameter("name","123").addParameter("age",18);
//add more complex attribute to see do query demo
//result
mutation.addResultAttributes("code");
try {
GraphqlResponse response = client.doMutation(mutation);
//this map is graphql result
Map data = response.getData();
} catch (IOException e) {
e.printStackTrace();
}
mutation is
mutation{
updateUser(id:1,name:"123",age:18){
code
}
}
|
Complex structure request demo
Mutation demo,The query is consistent with the mutation.
@Test
public void testObjectParameter() throws IOException {
String serverUrl = "http://localhost:8080/graphql";
GraphqlClient graphqlClient = GraphqlClient.buildGraphqlClient(serverUrl);
Map<String,String> httpHeaders = new HashMap<>();
httpHeaders.put("token","graphqltesttoken");
graphqlClient.setHttpHeaders(httpHeaders);
GraphqlMutation mutation = new DefaultGraphqlMutation("addUser");
List<User> users = new ArrayList<>();
users.add(new User("tim",SexEnum.M));
users.add(new User("sdf",SexEnum.F));
mutation.getRequestParameter().addParameter("classId","123").addObjectParameter("users",users);
mutation.addResultAttributes("code");
System.out.println(mutation.toString());
}
/**
* test user
*/
class User{
public User(String name, SexEnum sexEnum) {
this.name = name;
this.sexEnum = sexEnum;
}
private String name;
private SexEnum sexEnum;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public SexEnum getSexEnum() {
return sexEnum;
}
public void setSexEnum(SexEnum sexEnum) {
this.sexEnum = sexEnum;
}
}
/**
* test user sex
*/
enum SexEnum{
M,
F
}
|
mutation is
mutation{
addUser(classId:"123",users:[{name:"tim",sexEnum:M},{name:"sdf",sexEnum:F}]){
code
}
} |
以上就是官方全部案例，即使你去百度得到的也不过是这些。
从案例中可以看出，请求有两种，一种是简单请求query，一种是复杂请求mutation。
要记住GraphQL的核心就是查询请求，无外乎封装条件。
所以GraphQL的查询请求很简单：
@PostMapping("/find")
// @RequestMapping(method = RequestMethod.POST, value = "/find")
public Result find() {
//1、graphql服务地址
String serverUrl = "https://api2.vetspire.com/graphql";
//2、build一个新的graphqlClient
GraphqlClient graphqlClient = GraphqlClient.buildGraphqlClient(serverUrl);
//3、使用Map来存储放入请求头，Authorization的密钥
Map<String, String> httpHeaders = new HashMap<>();
httpHeaders.put("Authorization", "SFMyNTY.g3QAAAACZAAEZGF0YW0AAAAIMTIxOjUxNDdkAAZzaWduZWRuBgA2HeSibwE.FSigojcmpREK5InTRp1iaxg_S2QQnz_Vd5_Z_PIlRQc");
//4、graphqlClient 设置http请求的头
graphqlClient.setHttpHeaders(httpHeaders);
//下面开始发一个简单的query请求查询
//创建一个query并设置query的名字为org，如果有特殊的需求自己继承GraphqlQuery
String queryMethodName = "org";
GraphqlQuery query = new DefaultGraphqlQuery(queryMethodName);
// 如果需要增加一些必要的参数则使用query.addParameter(""):
//设置需要查询的参数是id和name
query.addResultAttributes("id", "name");
//通过上面的信息进行查询
GraphqlResponse response = null;
try {
response = graphqlClient.doQuery(query);
} catch (IOException e) {
e.printStackTrace();
}
//获取数据，数据为map类型
Map result = response.getData();
System.out.println(result);
System.out.println(result.get("data"));
return new Result(true, StatusCode.SUCCESS.getCode(),result);
} |
复杂一点的是更新的请求，需要组装条件模仿GraphQL的格式，还要封装相应的实体类：
@GetMapping("/updatePatient")
public Result updatePatient() throws IOException {
//1、graphql服务地址
String serverUrl = "https://api2.vetspire.com/graphql";
//2、build一个新的graphqlClient
GraphqlClient graphqlClient = GraphqlClient.buildGraphqlClient(serverUrl);
//3、使用Map来存储放入请求头，Authorization的密钥
Map<String, String> httpHeaders = new HashMap<>();
httpHeaders.put("Authorization", "SFMyNTY.g3QAAAACZAAEZGF0YW0AAAAIMTIxOjUxNDdkAAZzaWduZWRuBgA2HeSibwE.FSigojcmpREK5InTRp1iaxg_S2QQnz_Vd5_Z_PIlRQc");
//4、graphqlClient 设置http请求的头
graphqlClient.setHttpHeaders(httpHeaders);
GraphqlMutation mutation = new DefaultGraphqlMutation("updatePatient");
//Patient patient = new Patient(24,"red");
Patient input = new Patient(24,"blue");
mutation.addParameter("id",847568).addObjectParameter("input",input);
mutation.addResultAttributes("id","name","birthDate","color","species","clientId","updatedAt","insertedAt","breed");
//addObjectParameter("patient",patient);
ResultAttributtes dataAttr = new ResultAttributtes("latestWeight");
mutation.addResultAttributes(dataAttr);
GraphqlResponse mutationResponse = graphqlClient.doMutation(mutation);
//同样返回的数据也是map的
Map result = mutationResponse.getData();
System.out.println(result);
System.out.println(result.get("data"));
return null;
}
class Patient{
public Integer getBirthDay() {
return birthDay;
}
public void setBirthDay(Integer birthDay) {
this.birthDay = birthDay;
}
public String getColor() {
return color;
}
public void setColor(String color) {
this.color = color;
}
private Integer birthDay;
private String color;
private String breed;
private String sex;
public String getBreed() {
return breed;
}
public void setBreed(String breed) {
this.breed = breed;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getSpecies() {
return species;
}
public void setSpecies(String species) {
this.species = species;
}
private String species;
public Patient(Integer birthDay,String color){
this.birthDay = birthDay;
this.color = color;
}
} |
对比官网示例，步骤就清晰明了了。
原文地址：https://blog.csdn.net/nonagontech/article/details/143524056
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