Java对接GraphQL

原创于 2024-11-05 19:49:29 发布 · 1.2k 阅读

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#java #graphql #开发语言

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。