Java使用OkHttps工具類調用外部接口

時間 2019-11-08

原文原文鏈接

前言java

如今公司業務已止不是傳統的增刪改查等簡單的業務處理操做，而是對數據各類聯調三方接口與其餘系統進行交互等，那麼就須要咱們在後臺java中進行外部接口的調用，本文采用OkHttps工具類對接微信接口爲你們簡單介紹下，java調用外部接口進行數據交互。mysql

第一步新建接口Demogit

本文采用Idea做爲開發工具 web

依次按照 file---new---projectspring

緊接着以下sql

若是這樣寫就會提示apache

由於Idea中建立項目-項目名稱必須小寫json

接着繼續勾選Jar依賴api

Jar依賴選擇完成以後，確認項目名稱跟所在目錄tomcat

更具體的步驟請查看公衆號以前寫的

學習棧新年獻禮-SpringBoot第一彈

項目建立好以後，建立兩個package，用來存放咱們的工具類，與接口

先引入項目所需jar包依賴

buildscript {
    ext {
        springBootVersion = '2.1.2.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}

apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
apply plugin: 'war'
group = 'com.ahdd99.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
    mavenCentral()
}

dependencies {
    compile 'org.springframework.boot:spring-boot-starter-data-jpa'
    compile 'org.springframework.boot:spring-boot-starter-jdbc'
    compile 'org.springframework.boot:spring-boot-starter-web'
    compile 'mysql:mysql-connector-java'
    compile 'org.springframework.boot:spring-boot-starter-test'
    compile 'com.squareup.okhttp3:okhttp:3.5.0'
    compile group: 'com.google.code.gson', name: 'gson', version: '2.7'
    compile 'com.xiaoleilu:hutool-all:3.1.0'
    compile 'com.squareup.okhttp3:okhttp:3.5.0'
    compileOnly 'org.projectlombok:lombok:1.16.6'
    testCompile 'org.springframework.boot:spring-boot-starter-test'
    providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
    providedRuntime 'org.apache.tomcat:tomcat-jasper:8.5.28'
}

緊接着，在util包裏面引入咱們的okhttps工具類

OkHttps工具類中主要封裝了get與post請求，這裏簡單讓你們看下，源代碼會貼在文章末尾

/**
 * OkHttpUtils 工具類
 */
@Slf4j
public class OkHttpUtils {

  private final static OkHttpClient client = new OkHttpClient().newBuilder()
      .writeTimeout(60, TimeUnit.SECONDS)
      .readTimeout(60, TimeUnit.SECONDS)
      .build();
  public static JsonObject doGetRetJson(String url) throws IOException {
    return doGetRetJsonElement(url).getAsJsonObject();
  }

  public static JsonElement doGetRetJsonElement(String url) throws IOException {
    Request request = new Request.Builder().url(url).build();
    return sendSyncRequestRetJsonElement(request);
  }

  public static JsonObject doPostRetJson(String url, String jsonBody) throws IOException {
    return doPostRetJsonElement(url, jsonBody).getAsJsonObject();
  }

  public static JsonElement doPostRetJsonElement(String url, String jsonBody) throws IOException {
    RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), jsonBody);
    Request request = new Request.Builder().url(url).post(requestBody).build();
    return sendSyncRequestRetJsonElement(request);
  }
  public static String doPostRetJsonString(String url, String jsonBody) throws IOException {
    RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), jsonBody);
    Request request = new Request.Builder().url(url).post(requestBody).build();
    return sendSyncRequestRetString(request);
  }
  public static String doPostRetString(String url, String textBody) throws IOException {
    RequestBody requestBody = RequestBody.create(MediaType.parse("application/x-www-form-urlencoded; charset=utf-8"), textBody);
    Request request = new Request.Builder().url(url).post(requestBody).build();
    return sendSyncRequestRetString(request);
  }

  public static void doPost(String url, Map<String, String> params) throws IOException {
    FormBody.Builder formBuilder = new FormBody.Builder();
    for (String key : params.keySet()) {
      formBuilder.add(key, params.get(key));
    }
    Request request = new Request.Builder().url(url).post(formBuilder.build()).build();
    sendSyncRequestRetString(request);
  }

  public static JsonObject doPostRetJson(String url, Map<String, String> params) throws IOException {
    FormBody.Builder formBuilder = new FormBody.Builder();
    for (String key : params.keySet()) {
      formBuilder.add(key, params.get(key));
    }
    Request request = new Request.Builder().url(url).post(formBuilder.build()).build();
    return sendSyncRequestRetJson(request);
  }

  /**
   * 支付寶請求返回form
   *
   * @param url
   * @param params
   * @return
   * @throws IOException   */
  public static String doPostResString(String url, Map<String, String> params) throws IOException {
    FormBody.Builder formBuilder = new FormBody.Builder();
    for (String key : params.keySet()) {
      formBuilder.add(key, params.get(key));
    }
    Request request = new Request.Builder().url(url).post(formBuilder.build()).build();
    return sendSyncRequestRetString(request);
  }

  public static JsonObject doPostRetJsonForUploadFile(String url, Map<String, Object> params) throws IOException {
    MultipartBody.Builder formBuilder = new MultipartBody.Builder();
    formBuilder.setType(MultipartBody.FORM);
    params.forEach((key, value) -> {
      if (value instanceof File) {
        File file = (File) value;
        formBuilder.addFormDataPart(key, file.getName(), RequestBody.create(MediaType.parse("application/pdf; charset=utf-8"), file));
      } else {
        formBuilder.addFormDataPart(key, value.toString());
      }
    });
    Request request = new Request.Builder().url(url).post(formBuilder.build()).build();
    return sendSyncRequestRetJson(request);
  }

  private static JsonObject sendSyncRequestRetJson(Request request) throws IOException {
    return sendSyncRequestRetJsonElement(request).getAsJsonObject();
  }

  private static JsonElement sendSyncRequestRetJsonElement(Request request) throws IOException {
    return JsonUtils.toJsonElement(sendSyncRequestRetString(request));
  }

  private static String sendSyncRequestRetString(Request request) throws IOException {
    Response response = client.newCall(request).execute();
    if (!response.isSuccessful()) {

      throw new IOException("請求出錯，出錯信息：" + response.message());
    }
    String retString = response.body().string();
    if (StrUtil.isEmpty(retString)) {
      return "";
    }
    return retString;
  }
}

kHttps工具類引入完成以後，引入JsonUtils工具類，這個主要是幫助咱們吧參數封給JSON，免去咱們在每一個接口中再進行單獨封裝

/**
 * 參數轉json工具類
 */
public class JsonUtils {

  private static final JsonParser JSON_PARSER = new JsonParser();
  public static String toJson(Object object) {
    Gson gson = new GsonBuilder().create();
    return gson.toJson(object);
  }

  public static JsonObject toJsonObject(String json) {
    return JSON_PARSER.parse(json).getAsJsonObject();
  }

  public static JsonArray jsonObjectToJsonArray(JsonObject jsonObject) {
    JsonArray jsonArray = new JsonArray();
    jsonArray.add(jsonObject);
    return jsonArray;
  }

  public static JsonElement toJsonElement(String json) {
    return JSON_PARSER.parse(json);
  }
}

工具類都引入完畢以後，就是咱們的重頭戲了

接口開發第一步，抽離接口Api工具類

將全部的接口路徑抽離爲工具類，而且定義爲常量，方便後期維護

/**
 * 接口api路徑
 * @author gyk
 * @date 2019-03-27 11:27
 */
public class WxPortApi {

    /**
     * 接口請求路徑
     */
    public final static  String WX_API = "https://api.weixin.qq.com";
    /**
     * 學習棧appID
     */
    public final  static  String WX_APP_ID = "";
    /**
     * 學習棧AppSecret
     */
    public final  static  String AppSecret = "";
    /**
     * 獲取access_token接口
     */
    public final static  String ACCESS_TOKEN = "/cgi-bin/token";
}

下來就是接口調用

建立package service

編寫接口service層業務處理

/**
 * 獲取公衆號的access_token
 * @param appId --- 微信appId
 * @param secret  --- 微信祕鑰
 * @return
 */
public JsonObject getAccessTocken(String appId, String secret){
    JsonObject resultJson = new JsonObject();
    Map<String, String> params = new HashMap<>(3);
    //賦值接口需傳遞參數
    //獲取access_token填寫client_credential
    params.put("grant_type", "client_credential");
    // 第三方用戶惟一憑證
    params.put("appid", appId);
    // 第三方用戶惟一憑證密鑰，即appSecret
    params.put("secret", secret);
    try {
        //調用okHttps工具類進行接口調用
        return OkHttpUtils.doPostRetJson(WxPortApi.WX_API + WxPortApi.ACCESS_TOKEN, params);
    } catch (IOException e) {
        //賦值失敗結果
        resultJson.addProperty("result","-1");
        resultJson.addProperty("msg",msg +"獲取access_token失敗");
        return resultJson;
    }

}

而後編寫單元測試

/**
 * 測試獲取公衆號的access_token
 */
@Test
public void getAccessTocken() {
    WxPortService wxPortService = new WxPortService();
    JsonObject jsonObject =  wxPortService.getAccessTocken(WxPortApi.WX_APP_ID, WxPortApi.AppSecret);
    //獲取錯誤碼
    String error_code = String.valueOf(jsonObject.get("errcode"));
    //若是errcode 爲空，那麼證實獲取的正確，否則獲取失敗
    if("null".equals(error_code)){
        //打印獲得的access_token
        System.out.println(String.valueOf(jsonObject.get("access_token")));
    }
    
}

在這裏有一個小坑你們要注意，java中String.valueOf() 若是你傳入的是NULL 那麼java會給你返回"Null" 字符串

剩下的微信接口對接將於後面進一步詳細講解

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源碼地址 https://gitee.com/DaiDaiDeXiaoMaNong/port.git