How to use the REST service in BPM (1): Access webpage content through a program

 

This article mainly describes how to access webpage content through a program, which is the basis for accessing the REST service.

In Java, we can use the HttpUrlConnection class. The Code is as follows.

1 package http. base; 2 3 import java. io. bufferedReader; 4 import java. io. IOException; 5 import java. io. inputStream; 6 import java. io. inputStreamReader; 7 import java.net. httpURLConnection; 8 import java.net. URL; 9 import java. nio. charset. charset; 10 import java. util. map; 11 import java. util. vector; 12 13 14 public class HttpRequester {15 private String defaultContentEncoding; 16 17 public HttpRequ Ester () {18 this. defaultContentEncoding = Charset. defaultCharset (). name (); 19} 20 21 public HttpResponse sendGet (String urlString) throws IOException {22 return this. send (urlString, "GET", null, null); 23} 24 25 public HttpResponse sendGet (String urlString, Map <String, String> params) 26 throws IOException {27 return this. send (urlString, "GET", params, null); 28} 29 30 public HttpResponse NdGet (String urlString, Map <String, String> params, 31 Map <String, String> propertys) throws IOException {32 return this. send (urlString, "GET", params, propertys); 33} 34 35 public HttpResponse sendPost (String urlString) throws IOException {36 return this. send (urlString, "POST", null, null); 37} 38 39 public HttpResponse sendPost (String urlString, Map <String, String> params) 40 throws IOExcept Ion {41 return this. send (urlString, "POST", params, null); 42} 43 44 public HttpResponse sendPost (String urlString, Map <String, String> params, 45 Map <String, string> propertys) throws IOException {46 return this. send (urlString, "POST", params, propertys); 47} 48 49 private HttpResponse send (String urlString, String method, 50 Map <String, String> parameters, Map <String, string> propertys) 51 t Hrows IOException {52 HttpURLConnection urlConnection = null; 53 54 if (method. inclusignorecase ("GET") & parameters! = Null) {55 StringBuffer param = new StringBuffer (); 56 int I = 0; 57 for (String key: parameters. keySet () {58 if (I = 0) 59 param. append ("? "); 60 else 61 param. append ("&"); 62 param. append (key ). append ("= "). append (parameters. get (key); 63 I ++; 64} 65 urlString + = param; 66} 67 URL url = new URL (urlString); 68 urlConnection = (HttpURLConnection) url. openConnection (); 69 70 urlConnection. setRequestMethod (method); 71 urlConnection. setDoOutput (true); 72 urlConnection. setDoInput (true); 73 urlConnection. setUseCaches (false); 74 75 if (prope Rtys! = Null) 76 for (String key: propertys. keySet () {77 urlConnection. addRequestProperty (key, propertys. get (key); 78} 79 80 if (method. equalsIgnoreCase ("POST") & parameters! = Null) {81 StringBuffer param = new StringBuffer (); 82 for (String key: parameters. keySet () {83 param. append ("&"); 84 param. append (key ). append ("= "). append (parameters. get (key); 85} 86 urlConnection. getOutputStream (). write (param. toString (). getBytes (); 87 urlConnection. getOutputStream (). flush (); 88 urlConnection. getOutputStream (). close (); 89} 90 91 return this. makeContent (urlString, urlConnec Tion); 92} 93 94 private HttpResponse makeContent (String urlString, 95 HttpURLConnection urlConnection) throws IOException {96 HttpResponse httpResponser = new HttpResponse (); 97 try {98 InputStream in = urlConnection. getInputStream (); 99 BufferedReader bufferedReader = new BufferedReader (100 new InputStreamReader (in); 101 httpResponser. contentCollection = new Vector <String> (); 102 StringBuffer Temp = new StringBuffer (); 103 String line = bufferedReader. readLine (); 104 while (line! = Null) {105 httpResponser. contentCollection. add (line); 106 temp. append (line ). append ("/r/n"); 107 line = bufferedReader. readLine (); 108} 109 bufferedReader. close (); 110 111 String ecod = urlConnection. getContentEncoding (); 112 if (ecod = null) 113 ecod = this. defaultContentEncoding; 114 115 httpResponser. urlString = urlString; 116 117 httpResponser. defaultPort = urlConnection. getURL (). getDefaultPort (); 118 HttpResponser. file = urlConnection. getURL (). getFile (); 119 httpResponser. host = urlConnection. getURL (). getHost (); 120 httpResponser. path = urlConnection. getURL (). getPath (); 121 httpResponser. port = urlConnection. getURL (). getPort (); 122 httpResponser. protocol = urlConnection. getURL (). getProtocol (); 123 httpResponser. query = urlConnection. getURL (). getQuery (); 124 httpResponser. ref = urlConnection. getURL (). GetRef (); 125 httpResponser. userInfo = urlConnection. getURL (). getUserInfo (); 126 127 httpResponser. content = new String (temp. toString (). getBytes (), ecod); 128 httpResponser. contentEncoding = ecod; 129 httpResponser. code = urlConnection. getResponseCode (); 130 httpResponser. message = urlConnection. getResponseMessage (); 131 httpResponser. contentType = urlConnection. getContentType (); 132 httpResponser. meth Od = urlConnection. getRequestMethod (); 133 httpResponser. connectTimeout = urlConnection. getConnectTimeout (); 134 httpResponser. readTimeout = urlConnection. getReadTimeout (); 135 136 return httpResponser; 137} catch (IOException e) {138 throw e; 139} finally {140 if (urlConnection! = Null) 141 urlConnection. disconnect (); 142} 143} 144 145 public String getdefacontcontentencoding () {146 return this. defaultContentEncoding; 147} 148 149 public void setdefacontcontentencoding (String defaultContentEncoding) {150 this. defaultContentEncoding = defaultContentEncoding; 151} 152}HttpRequest Class 1 package http. base; 2 3 import java. util. vector; 4 5 public class HttpResponse {6 7 String urlString; 8 int defaultPort; 9 String file; 10 String host; 11 String path; 12 int port; 13 String protocol; 14 String query; 15 String ref; 16 String userInfo; 17 String contentEncoding; 18 String content; 19 String contentType; 20 int code; 21 String message; 22 String method; 23 int connectTimeout; 24 int readTimeout; 25 Vector <String> contentCollection; 26 27 public String getContent () {28 return content; 29} 30 31 public String getContentType () {32 return contentType; 33} 34 35 public int getCode () {36 return code; 37} 38 39 public String getMessage () {40 return message; 41} 42 43 public Vector <String> getContentCollection () {44 return contentCollection; 45} 46 47 public String getContentEncoding () {48 return contentEncoding; 49} 50 51 public String getMethod () {52 return method; 53} 54 55 public int getConnectTimeout () {56 return connectTimeout; 57} 58 59 public int getReadTimeout () {60 return readTimeout; 61} 62 63 public String getUrlString () {64 return urlString; 65} 66 67 public int getDefaultPort () {68 return defaultPort; 69} 70 71 public String getFile () {72 return file; 73} 74 75 public String getHost () {76 return host; 77} 78 79 public String getPath () {80 return path; 81} 82 83 public int getPort () {84 return port; 85} 86 87 public String getProtocol () {88 return protocol; 89} 90 91 public String getQuery () {92 return query; 93} 94 95 public String getRef () {96 return ref; 97} 98 99 public String getUserInfo () {100 return userInfo; 101} 102 103}HttpResponse class

Below is a simple test class.

1 package http. base; 2 3 public class HttpTest {4 public static void main (String [] args) {5 try {6 HttpRequester request = new HttpRequester (); 7 HttpResponse hr = request. sendGet ("http://www.baidu.com"); 8 9 System. out. println (hr. getUrlString (); 10 System. out. println (hr. getProtocol (); 11 System. out. println (hr. getHost (); 12 System. out. println (hr. getPort (); 13 System. out. println (hr. getContentEncoding (); 14 System. out. println (hr. getMethod (); 15 16 System. out. println (hr. getContent (); 17 18} catch (Exception e) {19 e. printStackTrace (); 20} 21} 22}View Code

Because the return values of the REST service are generally JSON objects, in the next article, we will look at how to convert Java objects and JSON objects.