本篇參考Trail教程：
https://developer.salesforce.com/trailhead/force_com_dev_intermediate/apex_integration_services/apex_integration_rest_callouts
有的時候我們需要在salesforce中引入外部的方法或者資料，這樣就需要通路外部的Services，目前常用的通路方式有兩種：
1.SOAP方式：Web Service通過XML方式調用SOAP Web伺服器;
2.REST方式：Http通過JSON使用REST方式調用伺服器。
這兩種Callouts使用原理類似，簡單的可以了解像伺服器發送一個請求，然後伺服器傳回一個響應。基于WSDL的callouts适用于SOAP方式，HTTP方式可以使用任何的HTTP service，SOAP或者REST都可以。
這兩種方式能選擇Http方式盡量選擇Http方式。
下面來了解一下REST方式擷取外部Service資料以及其他Service通路Salesforce資料操作。
一.REST方式擷取外部Service資料
REST方式主要原理如下圖所示。使用REST方式主要步驟如下：
salesforce通過REST方式通路外界站點步驟如下：
1.将Web Service的授權端點位址添加到Remote Site中：setup->Administer->Security Site Settings->Remote Site Settings。
salesforce提供了兩個測試URL，将兩個測試的URL添加到Remote Site中。兩個URL分别為：
http:https://ap2.salesforce.com/0rp28000000TSqv
soap:https://ap2.salesforce.com/0rp28000000TSr0
2.代碼進行通路
通過HTTP方式可以使用以下方法進行相關操作的通路
https://th-apex-http-callout.herokuapp.com/animals遠端站點JSON内容如下{"animals":["majestic badger","fluffy bunny","scary bear","chicken"]}
在Eclipse中使用匿名塊編寫代碼實作通路：window->show view->Other->Execute Anonymous即可打開匿名塊。 GET方式擷取資料：
Http http = new Http();
HttpRequest request = new HttpRequest();
request.setEndpoint('https://th-apex-http-callout.herokuapp.com/animals');
request.setMethod('GET');
HttpResponse response = http.send(request);
// If the request is successful, parse the JSON response.
if (response.getStatusCode() == 200) {
// Deserialize the JSON string into collections of primitive data types.
Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
// Cast the values in the 'animals' key as a list
List<Object> animals = (List<Object>) results.get('animals');
System.debug('Received the following animals:');
for (Object animal: animals) {
System.debug(animal);
}
} 輸出的結果如下：
其他方式自行測試。
二.Salesforce作為REST Service供java通路（可以供其它語言通路，這裡隻對java展示，因為我隻會java）
有的時候我們需要在其他平台上擷取sfdc端的資料，比如做android項目需要通路sfdc資料，那樣就需要Salesforce作為Service，java端通過http擷取并對資料進行相關操作。步驟如下：
1)建立一個App，然後建立Connected App:
setup->Build->Create->Apps.先new一個app，正常new完以後new一個Connected App，設定Enable OAuth Settings為true，截圖如下所示：
java通路sfdc 的Service的時候需要用到Consumer Key以及Consumer Secret這兩項。
2）sfdc端rest service建構：這裡我們以Goods__c進行操作，主要方法有添加一條Goods，通過Id擷取Goods，通過PageNumber擷取指定條數開始的Goods資料，修改一條Goods以及删除一條Goods。
這裡對常用的注解進行解釋：
1.@RestResource:曝光此類作為REST資源;
2.@HttpGet:曝光方法作為REST資源，當有Http get請求發送時，此注解對應的方法會被執行;
3.@HttpPost:Http post 請求發送時，此注解對應的方法會被執行;
4.@HttpDelete:當有Http delete請求發送時，此注解對應的方法會被執行;
5.@HttpPut:當有Http put請求發送時，此注解對應的方法會被執行;
6.@HttpPatch:當有Http patch請求發送時，此注解對應的方法會被執行。
因為http有請求時按照請求方式來對應相關方法，是以一個類中上述标簽隻能存在一個，即不能存在兩個方法标注@HttpRequest等。
1 /*
2 * 使用salesforce通過REST方式作為webservice，需要以下幾點：
3 * 1.類和方法需要global，方法需要靜态
4 * 2.類需要通過RestResource（UrlMapping='/page/*'）注解聲明
5 * 3.@HttpGet和@HttpDelete不能有形參，可以通過URL?param或者URL/param方式傳過來參數
6 */
7 @RestResource(UrlMapping='/Goods/*')
8 global class GoodsRESTController {
9 global static final Integer PAGE_SIZE = 20;
10 @HttpGet
11 global static List<Goods__c> getGoodsByIdOrGoodsList() {
12 RestRequest request = RestContext.request;
13 // grab the goodsId from the end of the URL
14 String currentPage = request.params.get('currentPage') != null ? request.params.get('currentPage') : '0';
15 Integer offsetNumber = Integer.valueOf(currentPage) * PAGE_SIZE;
16 String goodsId = request.params.get('goodsId');
17 String fetchSql;
18 if(goodsId != null) {
19 fetchSql = 'SELECT CreatedById, CreatedDate, IsDeleted, Name,' +
20 ' GoodsBrand__c, GoodsCostPrice__c, GoodsDescribe__c, GoodsName__c,' +
21 ' GoodsPrice__c, GoodsProfit__c, LastActivityDate, LastModifiedById,' +
22 ' LastModifiedDate, No__c, OwnerId, Id FROM Goods__c' +
23 ' where Id = :goodsId';
24 } else {
25 fetchSql = 'SELECT CreatedById, CreatedDate, IsDeleted, Name,' +
26 ' GoodsBrand__c, GoodsCostPrice__c, GoodsDescribe__c, GoodsName__c,' +
27 ' GoodsPrice__c, GoodsProfit__c, LastActivityDate, LastModifiedById,' +
28 ' LastModifiedDate, No__c, OwnerId, Id FROM Goods__c limit :PAGE_SIZE offset :offsetNumber';
29 }
30 List<Goods__c> goodsList = Database.query(fetchSql);
31 return goodsList;
32 }
33
34
35 @HttpPost
36 global static Id insertGoods(String goodsName,String goodsBrand,String goodsPrice,String goodsCostPrice,String goodsDescribe) {
37 System.debug('---------goodsName-------------' + goodsName);
38 Goods__c goods = new Goods__c();
39 if(goodsPrice != null && goodsPrice.isNumeric()) {
40 goods.GoodsPrice__c = Double.valueOf(goodsPrice);
41 }
42 if(goodsCostPrice != null && goodsCostPrice.isNumeric()) {
43 goods.GoodsCostPrice__c = Double.valueOf(goodsCostPrice);
44 }
45 goods.GoodsName__c = goodsName;
46 goods.GoodsDescribe__c = goodsDescribe;
47 insert goods;
48 return goods.Id;
49 }
50
51 @HttpDelete
52 global static void deleteGoods() {
53 RestRequest request = RestContext.request;
54 String goodsId = request.requestURI.substring(
55 request.requestURI.lastIndexOf('/')+1);
56 Goods__c needDeleteGoods = [select Id from Goods__c where Id = :goodsId];
57 if(needDeleteGoods != null) {
58 delete needDeleteGoods;
59 }
60 }
61
62 @HttpPut
63 global static ID upsertGoods(String id,String goodsName,String goodsBrand,String goodsPrice,String goodsCostPrice,String goodsDescribe) {
64 Goods__c goods = new Goods__c();
65 goods.Id = id;
66 goods.GoodsName__c = goodsName;
67 goods.GoodsBrand__c = goodsBrand;
68 goods.GoodsDescribe__c = goodsDescribe;
69 if(goodsPrice != null && goodsPrice.isNumeric()) {
70 goods.GoodsPrice__c = Double.valueOf(goodsPrice);
71 }
72 if(goodsCostPrice != null && goodsCostPrice.isNumeric()) {
73 goods.GoodsCostPrice__c = Double.valueOf(goodsCostPrice);
74 }
75 upsert goods;
76 return goods.Id;
77 }
78
79 @HttpPatch
80 global static ID updateGoods() {
81 RestRequest request = RestContext.request;
82 String goodsId = request.requestURI.substring(
83 request.requestURI.lastIndexOf('/')+1);
84 Goods__c goods = [select Id from Goods__c where Id= :goodsId];
85 // Deserialize the JSON string into name-value pairs
86 Map<String, Object> params = (Map<String, Object>)JSON.deserializeUntyped(request.requestbody.tostring());
87 // Iterate through each parameter field and value
88 goods.GoodsName__c = String.valueOf(params.get('GoodsName__c'));
89 goods.GoodsPrice__c = Double.valueOf(params.get('GoodsPrice__c'));
90 goods.GoodsCostPrice__c = Double.valueOf(params.get('GoodsCostPrice__c'));
91 update goods;
92 return goods.Id;
93 }
94
95
96
97 } 測試自己寫的方法可以在workbench中檢視，使用salesforce賬号登入workbench，https://workbench.developerforce.com/login.php.在這裡可以測試一下getGoodsByIdOrGoodsList方法，想要測試其他方法可以參看最上面的連結自行測試。如下圖所示：
3）java端通路sfdc的REST Service
java端通路sfdc的REST Service之前需要做兩部分，第一部分是下載下傳Http client的jar包，第二部分是下載下傳json的jar包。
1.Http client jar包下載下傳：通路http://hc.apache.org/downloads.cgi 選擇最新的jar包進行下載下傳，下載下傳後解壓，在lib目錄下位所需要的http client的jar包。
2.下載下傳json的jar包：http://mvnrepository.com/artifact/org.json/json。可以選擇下載下傳最新的json下載下傳後将json的jar和http client的jar放在一個檔案夾下，比如我們現在放在桌面的jars檔案夾下。
接下來打開eclipse，jars目錄下的jar包全都放在java項目裡，然後開始代碼通路階段。
1
2 import java.io.IOException;
3 import java.util.ArrayList;
4 import java.util.List;
5 import org.apache.http.Header;
6 import org.apache.http.HttpResponse;
7 import org.apache.http.HttpStatus;
8 import org.apache.http.client.ClientProtocolException;
9 import org.apache.http.client.HttpClient;
10 import org.apache.http.client.methods.HttpDelete;
11 import org.apache.http.client.methods.HttpGet;
12 import org.apache.http.client.methods.HttpPost;
13 import org.apache.http.entity.StringEntity;
14 import org.apache.http.impl.client.HttpClientBuilder;
15 import org.apache.http.message.BasicHeader;
16 import org.apache.http.util.EntityUtils;
17 import org.json.JSONArray;
18 import org.json.JSONException;
19 import org.json.JSONObject;
20 import org.json.JSONTokener;
21
22 public class InvokeGoodsByRestViaSFDC {
23
24 static final String USERNAME = "你的salesforce賬号";
25 static final String PASSWORD = "你的salesforce密碼+security token(如果有security token)";
26 static final String LOGINURL = "https://login.salesforce.com";
27 static final String GRANTSERVICE = "/services/oauth2/token?grant_type=password";
28 static final String CLIENTID = "3MVG9ZL0ppGP5UrBiKUS3jtHfmfz4eBCBEnuY0tIDByXVdtBJWeY6olTn1iLDNvP68EmfVtWE3IDzHOsMuDww";//上圖中Consumer Key
29 static final String CLIENTSECRET = "723866328398987848";//上圖中的Consumer Secret
30 private static String REST_ENDPOINT = "/services/apexrest" ;
31 private static String baseUri;
32 private static Header oauthHeader;
33 private static Header prettyPrintHeader = new BasicHeader("X-PrettyPrint", "1");
34
35 /**
36 * 判斷是否可以通路sfdc
37 * return：可以通路sfdc的rest則傳回true，否則傳回false
38 * */
39 private static boolean isAccessable() {
40 HttpClient httpclient = HttpClientBuilder.create().build();
41
42 // Assemble the login request URL
43 String loginURL = LOGINURL +
44 GRANTSERVICE +
45 "&client_id=" + CLIENTID +
46 "&client_secret=" + CLIENTSECRET +
47 "&username=" + USERNAME +
48 "&password=" + PASSWORD;
49
50 // Login requests must be POSTs
51 HttpPost httpPost = new HttpPost(loginURL);
52 HttpResponse response = null;
53 try {
54 // Execute the login POST request
55 response = httpclient.execute(httpPost);
56 } catch (ClientProtocolException cpException) {
57 cpException.printStackTrace();
58 } catch (IOException ioException) {
59 ioException.printStackTrace();
60 }
61 // verify response is HTTP OK
62 final int statusCode = response.getStatusLine().getStatusCode();
63 if (statusCode != HttpStatus.SC_OK) {
64 System.out.println("Error authenticating to Force.com: "+statusCode);
65 return false;
66 }
67
68 String getResult = null;
69 try {
70 getResult = EntityUtils.toString(response.getEntity());
71 } catch (IOException ioException) {
72 ioException.printStackTrace();
73 }
74
75 JSONObject jsonObject = null;
76 String loginAccessToken = null;
77 String loginInstanceUrl = null;
78
79 try {
80 jsonObject = (JSONObject) new JSONTokener(getResult).nextValue();
81 loginAccessToken = jsonObject.getString("access_token");
82 loginInstanceUrl = jsonObject.getString("instance_url");
83 } catch (JSONException jsonException) {
84 jsonException.printStackTrace();
85 }
86
87 baseUri = loginInstanceUrl + REST_ENDPOINT + "/Goods";
88 oauthHeader = new BasicHeader("Authorization", "OAuth " + loginAccessToken) ;
89 System.out.println("oauthHeader1: " + oauthHeader);
90 System.out.println(response.getStatusLine());
91 System.out.println("Successful login");
92 System.out.println("instance URL: "+loginInstanceUrl);
93 System.out.println("access token/session ID: "+loginAccessToken);
94 System.out.println("baseUri: "+ baseUri);
95 return true;
96 }
97
98
99 public static void main(String[] args) {
100 createGoods("小米4","小米","2500","2000","測試商品描述資訊：小米");
101 //deleteGoods("a052800000880mlAAA");
102 Goods getGoods = getGoodsById("a0528000008811qAAA");
103 if(getGoods != null) {
104 System.out.println("goods Name :" + getGoods.getGoodsName());
105 System.out.println("goods Price : " + getGoods.getGoodsPrice());
106 System.out.println("goods cost price :" +getGoods.getGoodsCostPrice());
107 System.out.println("goods brand : " + getGoods.getGoodsBrand());
108 }
109 List<Goods> goodsList = getGoodsList(0);
110 System.out.println(goodsList.toString());
111
112 Goods updateGoods = new Goods();
113 updateGoods.setGoodsId("a0528000008811qAAA");
114 updateGoods.setGoodsName("test goods Name");
115 updateGoods.setGoodsPrice("10000");
116 updateGoods.setGoodsCostPrice("8000");
117 updateGoods(updateGoods);
118 }
119
120
121
122
123 // Create Goods using REST HttpPost
124 public static void createGoods(String goodsName,String goodsBrand,String goodsPrice,String goodsCostPrice,String goodsDescribe) {
125 try {
126 if(isAccessable()) {
127 String uri = baseUri + "/createGoods";
128 JSONObject goods = new JSONObject();
129 goods.put("goodsName", goodsName);
130 goods.put("goodsBrand", goodsBrand);
131 goods.put("goodsPrice", goodsPrice);
132 goods.put("goodsCostPrice",goodsCostPrice);
133 goods.put("goodsDescribe", goodsDescribe);
134
135 System.out.println("JSON for goods record to be inserted:\n" + goods.toString(1));
136 //Construct the objects needed for the request
137 HttpClient httpClient = HttpClientBuilder.create().build();
138 System.out.println("oauthHeader" + oauthHeader);
139 HttpPost httpPost = new HttpPost(uri);
140 httpPost.addHeader(oauthHeader);
141 httpPost.addHeader(prettyPrintHeader);
142 httpPost.addHeader("encoding", "UTF-8");
143 // The message we are going to post
144 StringEntity body = new StringEntity(goods.toString(1));
145 body.setContentType("application/json");
146 httpPost.setEntity(body);
147
148 //Make the request
149 HttpResponse response = httpClient.execute(httpPost);
150 System.out.print("response : " + response.toString());
151 //Process the results
152 int statusCode = response.getStatusLine().getStatusCode();
153 System.out.println("status code : " + statusCode);
154 if (statusCode == HttpStatus.SC_OK) {
155 String response_string = EntityUtils.toString(response.getEntity());
156 if(response_string != null ) {
157 System.out.println("New Goods id from response: " + response_string);
158 }
159 } else {
160 System.out.println("Insertion unsuccessful. Status code returned is " + statusCode);
161 }
162 httpPost.releaseConnection();
163 }
164 } catch (JSONException e) {
165 System.out.println("Issue creating JSON or processing results");
166 e.printStackTrace();
167 } catch (IOException ioe) {
168 ioe.printStackTrace();
169 } catch (NullPointerException npe) {
170 npe.printStackTrace();
171 }
172 }
173
174 public static void deleteGoods(String goodsId) {
175 try {
176 if(isAccessable()) {
177 String uri = baseUri + "/deleteGoods" + "/" + goodsId;
178 HttpClient httpClient = HttpClientBuilder.create().build();
179
180 HttpDelete httpDelete = new HttpDelete(uri);
181 httpDelete.addHeader(oauthHeader);
182 httpDelete.addHeader(prettyPrintHeader);
183
184 //Make the request
185 HttpResponse response = httpClient.execute(httpDelete);
186
187 //Process the response
188 int statusCode = response.getStatusLine().getStatusCode();
189 if (statusCode == HttpStatus.SC_OK) {
190 System.out.println("Deleted the goods successfully.");
191 } else {
192 System.out.println("goods delete NOT successful. Status code is " + statusCode);
193 }
194 httpDelete.releaseConnection();
195 }
196 } catch (JSONException e) {
197 System.out.println("Issue creating JSON or processing results");
198 e.printStackTrace();
199 } catch (IOException ioe) {
200 ioe.printStackTrace();
201 } catch (NullPointerException npe) {
202 npe.printStackTrace();
203 }
204 }
205
206 public static List<Goods> getGoodsList(Integer pageNumber) {
207 try {
208 if(isAccessable()) {
209 String uri = baseUri + "/getGoodsByIdOrGoodsList" + "？currentPage=" + pageNumber;
210 HttpClient httpClient = HttpClientBuilder.create().build();
211 HttpGet httpGet = new HttpGet(uri);
212 httpGet.addHeader(oauthHeader);
213 httpGet.addHeader(prettyPrintHeader);
214 //Make the request
215 HttpResponse response = httpClient.execute(httpGet);
216 //Process the response
217 int statusCode = response.getStatusLine().getStatusCode();
218 if (statusCode == HttpStatus.SC_OK) {
219 List<Goods> goodsList = new ArrayList<Goods>();
220 String response_string = EntityUtils.toString(response.getEntity());
221 System.out.println("response_string : " + response_string);
222 JSONArray jsonArray = new JSONArray(response_string);
223 JSONObject jsonObject = null;
224 for(int i=0;i<jsonArray.length();i++) {
225 jsonObject = jsonArray.getJSONObject(i);
226 Goods goods = new Goods();
227 if(jsonObject != null) {
228 goods.setGoodsName(jsonObject.getString("GoodsName__c"));
229 goods.setGoodsPrice(String.valueOf(jsonObject.getDouble("GoodsPrice__c")));
230 goods.setGoodsCostPrice(String.valueOf(jsonObject.getDouble("GoodsCostPrice__c")));
231 goods.setGoodsDescribe(jsonObject.getString("GoodsDescribe__c"));
232 goodsList.add(goods);
233 }
234 }
235 return goodsList;
236 } else {
237 return null;
238 }
239 }
240 }catch (JSONException e) {
241 System.out.println("Issue creating JSON or processing results");
242 e.printStackTrace();
243 } catch (IOException ioe) {
244 ioe.printStackTrace();
245 } catch (NullPointerException npe) {
246 npe.printStackTrace();
247 }
248 return null;
249 }
250
251 public static Goods getGoodsById(String goodsId) {
252 try {
253 if(isAccessable()) {
254 String uri = baseUri + "/getGoodsByIdOrGoodsList" + "？goodsId=" + goodsId;
255 HttpClient httpClient = HttpClientBuilder.create().build();
256
257 HttpGet httpGet = new HttpGet(uri);
258 httpGet.addHeader(oauthHeader);
259 httpGet.addHeader(prettyPrintHeader);
260
261 //Make the request
262 HttpResponse response = httpClient.execute(httpGet);
263
264 //Process the response
265 int statusCode = response.getStatusLine().getStatusCode();
266 if (statusCode == HttpStatus.SC_OK) {
267 String response_string = EntityUtils.toString(response.getEntity());
268 System.out.println("response_string : " + response_string);
269 JSONArray jsonArray = new JSONArray(response_string);
270 JSONObject jsonObject = null;
271 if(jsonArray.length() > 0) {
272 jsonObject = jsonArray.getJSONObject(0);
273 }
274
275 Goods goods = new Goods();
276 if(jsonObject != null) {
277 goods.setGoodsName(jsonObject.getString("GoodsName__c"));
278 goods.setGoodsPrice(String.valueOf(jsonObject.getDouble("GoodsPrice__c")));
279 goods.setGoodsCostPrice(String.valueOf(jsonObject.getDouble("GoodsCostPrice__c")));
280 goods.setGoodsDescribe(jsonObject.getString("GoodsDescribe__c"));
281 }
282 //goods.setGoodsBrand(jsonObject.getString("GoodsBrand__c"));
283 return goods;
284 } else {
285 return null;
286 }
287 }
288 } catch (JSONException e) {
289 System.out.println("Issue creating JSON or processing results");
290 e.printStackTrace();
291 } catch (IOException ioe) {
292 ioe.printStackTrace();
293 } catch (NullPointerException npe) {
294 npe.printStackTrace();
295 }
296 return null;
297 }
298
299 public static void updateGoods(Goods updateGoods) {
300 try {
301 if(isAccessable()) {
302 String uri = baseUri + "/updateGoods/"+updateGoods.getGoodsId();
303 JSONObject goods = new JSONObject();
304 goods.put("GoodsName__c", updateGoods.getGoodsName());
305 goods.put("GoodsPrice__c", updateGoods.getGoodsPrice());
306 goods.put("GoodsCostPrice__c", updateGoods.getGoodsCostPrice());
307 org.apache.http.client.methods.HttpPatch httpPatch = new org.apache.http.client.methods.HttpPatch(uri);
308 HttpClient httpClient = HttpClientBuilder.create().build();
309 httpPatch.addHeader(oauthHeader);
310 httpPatch.addHeader(prettyPrintHeader);
311 StringEntity body = new StringEntity(goods.toString(1));
312 body.setContentType("application/json");
313 httpPatch.setEntity(body);
314
315 //Make the request
316 HttpResponse response = httpClient.execute(httpPatch);
317
318 //Process the response
319 int statusCode = response.getStatusLine().getStatusCode();
320 if (statusCode == HttpStatus.SC_OK) {
321 System.out.println("Updated the goods successfully.");
322 } else {
323 System.out.println("Goods update NOT successfully. Status code is " + statusCode);
324 }
325 }
326 }catch (JSONException e) {
327 System.out.println("Issue creating JSON or processing results");
328 e.printStackTrace();
329 } catch (IOException ioe) {
330 ioe.printStackTrace();
331 } catch (NullPointerException npe) {
332 npe.printStackTrace();
333 }
334 }
335
336
337 } 我們隻對getGoodsById方法進行測試，下圖為顯示結果。
java通路sfdc的rest service需要OAuth身份認證，通過使用者名密碼，以及custom key 和custom password以及通路的apexrest連結即可以通路相應的rest service資源。
總結：本篇描述的主要是sfdc如何通過rest方式擷取外部平台的資源以及sfdc如何作為rest service供外部平台調用，每個人的賬号密碼，以及custom key 和custom password不相同，copy代碼後修改這幾處地方，如果restResource以及相應注解對應的方法不同，也需要修改相應的方法。此篇文章的缺點為沒有考慮中文内容的問題，通過insert等方法存儲到伺服器會導緻中文亂碼現象，有需要的可以自行對資料進行編碼解碼處理。
作者：zero
部落格位址：http://www.cnblogs.com/zero-zyq/
本文歡迎轉載，但未經作者同意必須保留此段聲明，且在文章頁面明顯位置給出原文連接配接
個人下載下傳了一些相關學習的PDF檔案，如果需要下載下傳請通路百度雲 點選此處通路 密碼：jhuy
如果文章的内容對你有幫助，歡迎點贊~
為友善手機端檢視部落格，現正在将部落格遷移至微信公衆号：Salesforce零基礎學習，歡迎各位關注。