java如何在一个项目调另一个项目中“post--/project/v1/mdg/identity/project/queryAllProject”类型的接口，并举例？

Java可以使用HttpURLConnection或者HttpClient这两个类库调用其他项目的接口。

下面是使用HttpClient调用其他项目接口的示例代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class HttpClientExample {
    public static void main(String[] args) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("http://example.com/project/v1/mdg/identity/project/queryAllProject");

        List<NameValuePair> params = new ArrayList<>();
        params.add(new BasicNameValuePair("param1", "value1"));
        params.add(new BasicNameValuePair("param2", "value2"));

        try {
            httpPost.setEntity(new UrlEncodedFormEntity(params, StandardCharsets.UTF_8));

            HttpResponse response = httpClient.execute(httpPost);
            HttpEntity entity = response.getEntity();

            if (entity != null) {
                InputStream instream = entity.getContent();
                BufferedReader reader = new BufferedReader(new InputStreamReader(instream));
                String line;
                while ((line = reader.readLine()) != null) {
                    System.out.println(line);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

在上面的代码中，我们使用了HttpPost类来发送POST请求，并传递参数。params是一个List，包含了所有的参数名和参数值。UrlEncodedFormEntity类将params转换成了POST请求的参数格式。

需要注意的是，这里的URL是示例代码中的URL，需要替换成实际的接口URL。另外，如果接口需要传递JSON格式的数据，则需要使用HttpEntity和StringEntity类来构造请求体。