salesforce 零基础学习（三十三）通过REST方式访问外部数据以及JAVA通过rest方式访问salesforce

本篇参考Trail教程：

https://developer.salesforce.com/trailhead/force_com_dev_intermediate/apex_integration_services/apex_integration_rest_callouts

有的时候我们需要在salesforce中引入外部的方法或者数据，这样就需要访问外部的Services，目前常用的访问方式有两种：

1.SOAP方式：Web Service通过XML方式调用SOAP Web服务器;

2.REST方式：Http通过JSON使用REST方式调用服务器。

这两种Callouts使用原理类似，简单的可以理解像服务器发送一个请求，然后服务器返回一个响应。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。

这两种方式能选择Http方式尽量选择Http方式。

下面来了解一下REST方式获取外部Service数据以及其他Service访问Salesforce数据操作。

一.REST方式获取外部Service数据

REST方式主要原理如下图所示。使用REST方式主要步骤如下：

salesforce通过REST方式访问外界站点步骤如下：

1.将Web Service的授权端点地址添加到Remote Site中：setup->Administer->Security Site Settings->Remote Site Settings。

salesforce提供了两个测试URL，将两个测试的URL添加到Remote Site中。两个URL分别为：

http:https://ap2.salesforce.com/0rp28000000TSqv

soap:https://ap2.salesforce.com/0rp28000000TSr0

2.代码进行访问

通过HTTP方式可以使用以下方法进行相关操作的访问

https://th-apex-http-callout.herokuapp.com/animals远程站点JSON内容如下{"animals":["majestic badger","fluffy bunny","scary bear","chicken"]}

在Eclipse中使用匿名块编写代码实现访问：window->show view->Other->Execute Anonymous即可打开匿名块。

GET方式获取数据：

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);
    }
}

输出的结果如下：

其他方式自行测试。

二.Salesforce作为REST Service供java访问（可以供其它语言访问，这里只对java展示，因为我只会java）

有的时候我们需要在其他平台上获取sfdc端的数据，比如做android项目需要访问sfdc数据，那样就需要Salesforce作为Service，java端通过http获取并对数据进行相关操作。步骤如下：

1)新建一个App，然后创建Connected App:

setup->Build->Create->Apps.先new一个app，正常new完以后new一个Connected App，设置Enable OAuth Settings为true，截图如下所示：

java访问sfdc 的Service的时候需要用到Consumer Key以及Consumer Secret这两项。

2）sfdc端rest service构建：这里我们以Goods__c进行操作，主要方法有添加一条Goods，通过Id获取Goods，通过PageNumber获取指定条数开始的Goods数据，修改一条Goods以及删除一条Goods。

这里对常用的注解进行解释：

　　1.@RestResource:曝光此类作为REST资源;

　　2.@HttpGet:曝光方法作为REST资源，当有Http get请求发送时，此注解对应的方法会被执行;

　　3.@HttpPost:Http post 请求发送时，此注解对应的方法会被执行;

　　4.@HttpDelete:当有Http delete请求发送时，此注解对应的方法会被执行;

　　5.@HttpPut:当有Http put请求发送时，此注解对应的方法会被执行;

　　6.@HttpPatch:当有Http patch请求发送时，此注解对应的方法会被执行。

因为http有请求时按照请求方式来对应相关方法，所以一个类中上述标签只能存在一个，即不能存在两个方法标注@HttpRequest等。

 /*
 * 使用salesforce通过REST方式作为webservice，需要以下几点：
 * 1.类和方法需要global，方法需要静态
 * 2.类需要通过RestResource（UrlMapping='/page/*'）注解声明
 * 3.@HttpGet和@HttpDelete不能有形参，可以通过URL?param或者URL/param方式传过来参数
 */
 @RestResource(UrlMapping='/Goods/*')
 global class GoodsRESTController {
     global static final Integer PAGE_SIZE = 20;
     @HttpGet
     global static List<Goods__c> getGoodsByIdOrGoodsList() {
         RestRequest request = RestContext.request;
         // grab the goodsId from the end of the URL
         String currentPage = request.params.get('currentPage') != null ? request.params.get('currentPage') : '0';
         Integer offsetNumber = Integer.valueOf(currentPage) * PAGE_SIZE;
         String goodsId = request.params.get('goodsId');
         String fetchSql;
         if(goodsId != null) {
             fetchSql = 'SELECT CreatedById, CreatedDate, IsDeleted, Name,' +
             ' GoodsBrand__c, GoodsCostPrice__c, GoodsDescribe__c, GoodsName__c,' +
             ' GoodsPrice__c, GoodsProfit__c, LastActivityDate, LastModifiedById,' +
             ' LastModifiedDate, No__c, OwnerId, Id FROM Goods__c' +
             ' where Id = :goodsId';
         } else {
             fetchSql = 'SELECT CreatedById, CreatedDate, IsDeleted, Name,' +
             ' GoodsBrand__c, GoodsCostPrice__c, GoodsDescribe__c, GoodsName__c,' +
             ' GoodsPrice__c, GoodsProfit__c, LastActivityDate, LastModifiedById,' +
             ' LastModifiedDate, No__c, OwnerId, Id FROM Goods__c limit :PAGE_SIZE offset :offsetNumber';
         }
         List<Goods__c> goodsList = Database.query(fetchSql);
         return goodsList;
     }

     @HttpPost
     global static Id insertGoods(String goodsName,String goodsBrand,String goodsPrice,String goodsCostPrice,String goodsDescribe) {
         System.debug('---------goodsName-------------' + goodsName);
         Goods__c goods = new Goods__c();
         if(goodsPrice != null && goodsPrice.isNumeric()) {
             goods.GoodsPrice__c = Double.valueOf(goodsPrice);
         }
         if(goodsCostPrice != null && goodsCostPrice.isNumeric()) {
             goods.GoodsCostPrice__c = Double.valueOf(goodsCostPrice);
         }
         goods.GoodsName__c = goodsName;
         goods.GoodsDescribe__c = goodsDescribe;
         insert goods;
         return goods.Id;
     }

     @HttpDelete
     global static void deleteGoods() {
         RestRequest request = RestContext.request;
         String goodsId = request.requestURI.substring(
             request.requestURI.lastIndexOf('/')+1);
         Goods__c needDeleteGoods = [select Id from Goods__c where Id = :goodsId];
         if(needDeleteGoods != null) {
             delete needDeleteGoods;
         }
     }

     @HttpPut
     global static ID upsertGoods(String id,String goodsName,String goodsBrand,String goodsPrice,String goodsCostPrice,String goodsDescribe) {
         Goods__c goods = new Goods__c();
         goods.Id = id;
         goods.GoodsName__c = goodsName;
         goods.GoodsBrand__c = goodsBrand;
         goods.GoodsDescribe__c = goodsDescribe;
         if(goodsPrice != null && goodsPrice.isNumeric()) {
             goods.GoodsPrice__c = Double.valueOf(goodsPrice);
         }
         if(goodsCostPrice != null && goodsCostPrice.isNumeric()) {
             goods.GoodsCostPrice__c = Double.valueOf(goodsCostPrice);
         }
         upsert goods;
         return goods.Id;
     }

     @HttpPatch
     global static ID updateGoods() {
         RestRequest request = RestContext.request;
         String goodsId = request.requestURI.substring(
             request.requestURI.lastIndexOf('/')+1);
         Goods__c goods = [select Id from Goods__c where Id= :goodsId];
         // Deserialize the JSON string into name-value pairs
         Map<String, Object> params = (Map<String, Object>)JSON.deserializeUntyped(request.requestbody.tostring());
         // Iterate through each parameter field and value
         goods.GoodsName__c = String.valueOf(params.get('GoodsName__c'));
         goods.GoodsPrice__c = Double.valueOf(params.get('GoodsPrice__c'));
         goods.GoodsCostPrice__c = Double.valueOf(params.get('GoodsCostPrice__c'));
         update goods;
         return goods.Id;
     } 

 }

测试自己写的方法可以在workbench中查看，使用salesforce账号登录workbench，https://workbench.developerforce.com/login.php.在这里可以测试一下getGoodsByIdOrGoodsList方法，想要测试其他方法可以参看最上面的链接自行测试。如下图所示：

3）java端访问sfdc的REST Service

java端访问sfdc的REST Service之前需要做两部分，第一部分是下载Http client的jar包，第二部分是下载json的jar包。

1.Http client jar包下载：访问http://hc.apache.org/downloads.cgi 选择最新的jar包进行下载，下载后解压，在lib目录下位所需要的http client的jar包。

2.下载json的jar包：http://mvnrepository.com/artifact/org.json/json。可以选择下载最新的json下载后将json的jar和http client的jar放在一个文件夹下，比如我们现在放在桌面的jars文件夹下。

接下来打开eclipse，jars目录下的jar包全都放在java项目里，然后开始代码访问阶段。

 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import org.apache.http.Header;
 import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
 import org.apache.http.client.ClientProtocolException;
 import org.apache.http.client.HttpClient;
 import org.apache.http.client.methods.HttpDelete;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.message.BasicHeader;
 import org.apache.http.util.EntityUtils;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.json.JSONTokener;

 public class InvokeGoodsByRestViaSFDC {

     static final String USERNAME     = "你的salesforce账号";
     static final String PASSWORD     = "你的salesforce密码+security token(如果有security token)";
     static final String LOGINURL     = "https://login.salesforce.com";
     static final String GRANTSERVICE = "/services/oauth2/token?grant_type=password";
     static final String CLIENTID     = "3MVG9ZL0ppGP5UrBiKUS3jtHfmfz4eBCBEnuY0tIDByXVdtBJWeY6olTn1iLDNvP68EmfVtWE3IDzHOsMuDww";//上图中Consumer Key
     static final String CLIENTSECRET = "723866328398987848";//上图中的Consumer Secret
     private static String REST_ENDPOINT = "/services/apexrest" ;
     private static String baseUri;
     private static Header oauthHeader;
     private static Header prettyPrintHeader = new BasicHeader("X-PrettyPrint", "1");

     /**
      * 判断是否可以访问sfdc
      * return：可以访问sfdc的rest则返回true，否则返回false
      * */
     private static boolean isAccessable() {
         HttpClient httpclient = HttpClientBuilder.create().build();

         // Assemble the login request URL
         String loginURL = LOGINURL +
                           GRANTSERVICE +
                           "&client_id=" + CLIENTID +
                           "&client_secret=" + CLIENTSECRET +
                           "&username=" + USERNAME +
                           "&password=" + PASSWORD;

         // Login requests must be POSTs
         HttpPost httpPost = new HttpPost(loginURL);
         HttpResponse response = null;
         try {
             // Execute the login POST request
             response = httpclient.execute(httpPost);
         } catch (ClientProtocolException cpException) {
             cpException.printStackTrace();
         } catch (IOException ioException) {
             ioException.printStackTrace();
         }
         // verify response is HTTP OK
         final int statusCode = response.getStatusLine().getStatusCode();
         if (statusCode != HttpStatus.SC_OK) {
             System.out.println("Error authenticating to Force.com: "+statusCode);
             return false;
         }

         String getResult = null;
         try {
             getResult = EntityUtils.toString(response.getEntity());
         } catch (IOException ioException) {
             ioException.printStackTrace();
         }

         JSONObject jsonObject = null;
         String loginAccessToken = null;
         String loginInstanceUrl = null;

         try {
             jsonObject = (JSONObject) new JSONTokener(getResult).nextValue();
             loginAccessToken = jsonObject.getString("access_token");
             loginInstanceUrl = jsonObject.getString("instance_url");
         } catch (JSONException jsonException) {
             jsonException.printStackTrace();
         }

         baseUri = loginInstanceUrl + REST_ENDPOINT + "/Goods";
         oauthHeader = new BasicHeader("Authorization", "OAuth " + loginAccessToken) ;
         System.out.println("oauthHeader1: " + oauthHeader);
         System.out.println(response.getStatusLine());
         System.out.println("Successful login");
         System.out.println("instance URL: "+loginInstanceUrl);
         System.out.println("access token/session ID: "+loginAccessToken);
         System.out.println("baseUri: "+ baseUri);
         return true;
     }

     public static void main(String[] args) {
         createGoods("小米4","小米","2500","2000","测试商品描述信息：小米");
         //deleteGoods("a052800000880mlAAA");
         Goods getGoods = getGoodsById("a0528000008811qAAA");
         if(getGoods != null) {
             System.out.println("goods Name :" + getGoods.getGoodsName());
             System.out.println("goods Price : " + getGoods.getGoodsPrice());
             System.out.println("goods cost price :" +getGoods.getGoodsCostPrice());
             System.out.println("goods brand : " + getGoods.getGoodsBrand());
         }
         List<Goods> goodsList = getGoodsList(0);
         System.out.println(goodsList.toString());

         Goods updateGoods = new Goods();
         updateGoods.setGoodsId("a0528000008811qAAA");
         updateGoods.setGoodsName("test goods Name");
         updateGoods.setGoodsPrice("10000");
         updateGoods.setGoodsCostPrice("8000");
         updateGoods(updateGoods);
     }

     // Create Goods using REST HttpPost
     public static void createGoods(String goodsName,String goodsBrand,String goodsPrice,String goodsCostPrice,String goodsDescribe) {
         try {
             if(isAccessable()) {
                 String uri = baseUri + "/createGoods";
                 JSONObject goods = new JSONObject();
                 goods.put("goodsName", goodsName);
                 goods.put("goodsBrand", goodsBrand);
                 goods.put("goodsPrice", goodsPrice);
                 goods.put("goodsCostPrice",goodsCostPrice);
                 goods.put("goodsDescribe", goodsDescribe);

                 System.out.println("JSON for goods record to be inserted:\n" + goods.toString(1));
                 //Construct the objects needed for the request
                 HttpClient httpClient = HttpClientBuilder.create().build();
                 System.out.println("oauthHeader" + oauthHeader);
                 HttpPost httpPost = new HttpPost(uri);
                 httpPost.addHeader(oauthHeader);
                 httpPost.addHeader(prettyPrintHeader);
                 httpPost.addHeader("encoding", "UTF-8");
                 // The message we are going to post
                 StringEntity body = new StringEntity(goods.toString(1));
                 body.setContentType("application/json");
                 httpPost.setEntity(body);

                 //Make the request
                 HttpResponse response = httpClient.execute(httpPost);
                 System.out.print("response : " + response.toString());
                 //Process the results
                 int statusCode = response.getStatusLine().getStatusCode();
                 System.out.println("status code : " + statusCode);
                 if (statusCode == HttpStatus.SC_OK) {
                     String response_string = EntityUtils.toString(response.getEntity());
                     if(response_string != null ) {
                         System.out.println("New Goods id from response: " + response_string);
                     }
                 } else {
                     System.out.println("Insertion unsuccessful. Status code returned is " + statusCode);
                 }
                 httpPost.releaseConnection();
             }
         } catch (JSONException e) {
             System.out.println("Issue creating JSON or processing results");
             e.printStackTrace();
         } catch (IOException ioe) {
             ioe.printStackTrace();
         } catch (NullPointerException npe) {
             npe.printStackTrace();
         }
     }

     public static void deleteGoods(String goodsId) {
         try {
             if(isAccessable()) {
                 String uri = baseUri + "/deleteGoods" + "/" + goodsId;
                 HttpClient httpClient = HttpClientBuilder.create().build();

                 HttpDelete httpDelete = new HttpDelete(uri);
                 httpDelete.addHeader(oauthHeader);
                 httpDelete.addHeader(prettyPrintHeader);

                 //Make the request
                 HttpResponse response = httpClient.execute(httpDelete);

                 //Process the response
                 int statusCode = response.getStatusLine().getStatusCode();
                 if (statusCode == HttpStatus.SC_OK) {
                     System.out.println("Deleted the goods successfully.");
                 } else {
                     System.out.println("goods delete NOT successful. Status code is " + statusCode);
                 }
                 httpDelete.releaseConnection();
             }
         } catch (JSONException e) {
             System.out.println("Issue creating JSON or processing results");
             e.printStackTrace();
         } catch (IOException ioe) {
             ioe.printStackTrace();
         } catch (NullPointerException npe) {
             npe.printStackTrace();
         }
     }

     public static List<Goods> getGoodsList(Integer pageNumber) {
         try {
             if(isAccessable()) {
                 String uri = baseUri + "/getGoodsByIdOrGoodsList" + "？currentPage=" + pageNumber;
                 HttpClient httpClient = HttpClientBuilder.create().build();
                 HttpGet httpGet = new HttpGet(uri);
                 httpGet.addHeader(oauthHeader);
                 httpGet.addHeader(prettyPrintHeader);
                 //Make the request
                 HttpResponse response = httpClient.execute(httpGet);
                 //Process the response
                 int statusCode = response.getStatusLine().getStatusCode();
                 if (statusCode == HttpStatus.SC_OK) {
                     List<Goods> goodsList = new ArrayList<Goods>();
                     String response_string = EntityUtils.toString(response.getEntity());
                     System.out.println("response_string : " + response_string);
                     JSONArray jsonArray = new JSONArray(response_string);
                     JSONObject jsonObject = null;
                     for(int i=0;i<jsonArray.length();i++) {
                         jsonObject = jsonArray.getJSONObject(i);
                         Goods goods = new Goods();
                         if(jsonObject != null) {
                             goods.setGoodsName(jsonObject.getString("GoodsName__c"));
                             goods.setGoodsPrice(String.valueOf(jsonObject.getDouble("GoodsPrice__c")));
                             goods.setGoodsCostPrice(String.valueOf(jsonObject.getDouble("GoodsCostPrice__c")));
                             goods.setGoodsDescribe(jsonObject.getString("GoodsDescribe__c"));
                             goodsList.add(goods);
                         }
                     }
                     return goodsList;
             } else {
                 return null;
             }
             }
         }catch (JSONException e) {
             System.out.println("Issue creating JSON or processing results");
             e.printStackTrace();
         } catch (IOException ioe) {
             ioe.printStackTrace();
         } catch (NullPointerException npe) {
             npe.printStackTrace();
         }
         return null;
     }

     public static Goods  getGoodsById(String goodsId) {
         try {
             if(isAccessable()) {
                 String uri = baseUri + "/getGoodsByIdOrGoodsList" + "？goodsId=" + goodsId;
                 HttpClient httpClient = HttpClientBuilder.create().build();

                 HttpGet httpGet = new HttpGet(uri);
                 httpGet.addHeader(oauthHeader);
                 httpGet.addHeader(prettyPrintHeader);

                 //Make the request
                 HttpResponse response = httpClient.execute(httpGet);

                 //Process the response
                 int statusCode = response.getStatusLine().getStatusCode();
                 if (statusCode == HttpStatus.SC_OK) {
                     String response_string = EntityUtils.toString(response.getEntity());
                     System.out.println("response_string : " + response_string);
                     JSONArray jsonArray = new JSONArray(response_string);
                     JSONObject jsonObject = null;
                     if(jsonArray.length() > 0) {
                         jsonObject = jsonArray.getJSONObject(0);
                     }

                     Goods goods = new Goods();
                     if(jsonObject != null) {
                         goods.setGoodsName(jsonObject.getString("GoodsName__c"));
                         goods.setGoodsPrice(String.valueOf(jsonObject.getDouble("GoodsPrice__c")));
                         goods.setGoodsCostPrice(String.valueOf(jsonObject.getDouble("GoodsCostPrice__c")));
                         goods.setGoodsDescribe(jsonObject.getString("GoodsDescribe__c"));
                     }
                     //goods.setGoodsBrand(jsonObject.getString("GoodsBrand__c"));
                     return goods;
                 } else {
                     return null;
                 }
             }
         } catch (JSONException e) {
             System.out.println("Issue creating JSON or processing results");
             e.printStackTrace();
         } catch (IOException ioe) {
             ioe.printStackTrace();
         } catch (NullPointerException npe) {
             npe.printStackTrace();
         }
         return null;
     }

     public static void updateGoods(Goods updateGoods) {
         try {
             if(isAccessable()) {
                 String uri = baseUri + "/updateGoods/"+updateGoods.getGoodsId();
                 JSONObject goods = new JSONObject();
                 goods.put("GoodsName__c", updateGoods.getGoodsName());
                 goods.put("GoodsPrice__c", updateGoods.getGoodsPrice());
                 goods.put("GoodsCostPrice__c", updateGoods.getGoodsCostPrice());
                 org.apache.http.client.methods.HttpPatch httpPatch = new org.apache.http.client.methods.HttpPatch(uri);
                 HttpClient httpClient = HttpClientBuilder.create().build();
                 httpPatch.addHeader(oauthHeader);
                 httpPatch.addHeader(prettyPrintHeader);
                 StringEntity body = new StringEntity(goods.toString(1));
                 body.setContentType("application/json");
                 httpPatch.setEntity(body);

                 //Make the request
                 HttpResponse response = httpClient.execute(httpPatch);

                 //Process the response
                 int statusCode = response.getStatusLine().getStatusCode();
                 if (statusCode == HttpStatus.SC_OK) {
                     System.out.println("Updated the goods successfully.");
                 } else {
                     System.out.println("Goods update NOT successfully. Status code is " + statusCode);
                 }
             }
         }catch (JSONException e) {
             System.out.println("Issue creating JSON or processing results");
             e.printStackTrace();
         } catch (IOException ioe) {
             ioe.printStackTrace();
         } catch (NullPointerException npe) {
             npe.printStackTrace();
         }
     }

 }

我们只对getGoodsById方法进行测试，下图为显示结果。

java访问sfdc的rest service需要OAuth身份认证，通过用户名密码，以及custom key 和custom password以及访问的apexrest链接即可以访问相应的rest service资源。

总结：本篇描述的主要是sfdc如何通过rest方式获取外部平台的资源以及sfdc如何作为rest service供外部平台调用，每个人的账号密码，以及custom key 和custom password不相同，copy代码后修改这几处地方，如果restResource以及相应注解对应的方法不同，也需要修改相应的方法。此篇文章的缺点为没有考虑中文内容的问题，通过insert等方法存储到服务器会导致中文乱码现象，有需要的可以自行对数据进行编码解码处理。