用的 okhttp3 框架，首先封装四种请求方法

import net.sf.json.JSONObject;  
import okhttp3.*;  
import java.io.IOException;  
import java.util.HashMap;  
import java.util.Iterator;  

class TestMethod {  
    private static String baseUrl = "http://192.168.3.149:8080";  
    private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");  
    private static OkHttpClient client = new OkHttpClient();  
    //post请求  
    static Object doPost(String url, String json, String cookie) throws IOException {  
        RequestBody body = RequestBody.create(JSON, json);  
        Request request = new Request.Builder()  
                .url(baseUrl + url)  
                .addHeader("Cookie", cookie)  
                .post(body)  
                .build();  
        try (Response response = client.newCall(request).execute()) {  
            return JSONObject.fromObject(response.body().string());  
        }  
    }  
    //get请求  
    static Object doGet(String url, HashMap<String, Object> param, String cookie) throws IOException {  
    //拼接url字符串  
        if (param != null) {  
            Iterator<String> it = param.keySet().iterator();  
            StringBuffer sb = null;  
            while (it.hasNext()) {  
                String key = it.next();  
                Object value = param.get(key);  
                if (sb == null) {  
                    sb = new StringBuffer();  
                    sb.append("?");  
                } else {  
                    sb.append("&");  
                }  
                sb.append(key);  
                sb.append("=");  
                sb.append(value);  
            }  
            url += sb.toString();  
        }  
        Request request = new Request.Builder()  
                .url(baseUrl + url)  
                .addHeader("Cookie", cookie)  
                .get()  
                .build();  
        try (Response response = client.newCall(request).execute()) {  
            return JSONObject.fromObject(response.body().string());  
        }  
    }  
    //put请求  
    static Object doPut(String url, String json) throws IOException {  
        RequestBody body = RequestBody.create(JSON, json);  
        Request request = new Request.Builder()  
                .url(baseUrl + url)  
                .put(body)  
                .build();  
        try (Response response = client.newCall(request).execute()) {  
            return JSONObject.fromObject(response.body().string());  
        }  
    }  
    //delete请求  
    static Object doDelete(String url, String json) throws IOException {  
        RequestBody body = RequestBody.create(JSON, json);  
        Request request = new Request.Builder()  
                .url(baseUrl + url)  
                .delete(body)  
                .build();  
        try (Response response = client.newCall(request).execute()) {  
            return JSONObject.fromObject(response.body().string());  
        }  
    }  
}  

接下来是做 cookie 获取，把 cookie 保存到本地，在需要传递 cookie 的方法里调用

import okhttp3.*;  
import java.io.IOException;  

class Cookie {  
    private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");  
    private static OkHttpClient client = new OkHttpClient();  
    static String cookieManage() throws IOException {  
        String json = "{\"username\":\"huangshayang@supeq.com\",\"password\":\"123456\"}";  
        RequestBody body = RequestBody.create(JSON, json);  
        String cookieUrl = "http://192.168.3.149:8080/api/v1/login";  
        Request request = new Request.Builder()  
                .url(cookieUrl)  
                .post(body)  
                .build();  
        try (Response response = client.newCall(request).execute()) {  
            return response.header("Set-Cookie");  
        }  
    }  
}  

实际例子：登录请求和退出请求
1.登录请求不需要 cookie，所以不传

import net.sf.json.JSONObject;  
import java.io.IOException;  

public class LoginTest {  
    private static String loginUrl = "/api/v1/login";  
    //成功登录  
    public static JSONObject loginSuccess() throws IOException {  
        String json = "{\"username\":\"huangshayang@supeq.com\",\"password\":\"123456\"}";  
        return TestMethod.doPost(loginUrl, json, null);  
    }  
}  

2.退出请求需要 cookie

import net.sf.json.JSONObject;  
import java.io.IOException;  

public class LogoutTest {  
    private static String logoutUrl = "/api/v1/logout";  
    //成功退出  
    public static JSONObject logoutSuccess() throws IOException {  
        return TestMethod.doGet(logoutUrl, null, Cookie.cookieManage());  
    }  
}  

最后 junit 里做断言结果判断

import com.company.LoginTest;  
import com.company.LogoutTest;  
import net.sf.json.JSONObject;  
import org.junit.Test;  
import java.io.IOException;  
import static org.junit.Assert.assertEquals;  

public class ApiTest {  
    @Test  
    public void testloginSuccess() throws IOException {  
        JSONObject result = LoginTest.loginSuccess();  
        assertEquals(200, Integer.parseInt(result.getString("status")));  
        assertEquals("Operation is successful.", result.getString("message"));  
    }  
    @Test  
    public void testlogoutSuccess() throws IOException {  
        JSONObject result = LogoutTest.logoutSuccess();  
        assertEquals(200, Integer.parseInt(result.getString("status")));  
        assertEquals("Operation is successful.", result.getString("message"));  
    }  
}