java后台访问url连接——HttpClients
java后台访问url，并传递数据——通过httpclient方式
需要的包，包可能多几个额外的，如果无用或者冲突删除即可，httpclient是使用的是4.4.1的版本：http://download.csdn.net/detail/myfmyfmyfmyf/8894191
1、无参数传递，以微信开发为例，后台访问url连接获得全部的人员列表
/**
* 获取全部人员列表
* @return
*/
public JSONObject getAllEmployee(){
//获取微信号
String token=getTokenFromWx();
String dep_root=ROOT_DEP;//跟部门树
try {
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPost httpPost= new HttpPost("https://qyapi.weixin.qq.com/cgi-bin/user/list?access_token="+token+"&department_id="+dep_root+"&fetch_child="+FETCH_CHILD+"&status="+STATE);
// Create a custom response handler
ResponseHandler<JSONObject> responseHandler = new ResponseHandler<JSONObject>() {
//成功调用连接后，对返回数据进行的操作
public JSONObject handleResponse(
final HttpResponse response) throws ClientProtocolException, IOException {
int status = response.getStatusLine().getStatusCode();
if (status >= 200 && status < 300) {
//获得调用成功后 返回的数据
HttpEntity entity = response.getEntity();
if(null!=entity){
String result= EntityUtils.toString(entity);
//根据字符串生成JSON对象
JSONObject resultObj = JSONObject.fromObject(result);
return resultObj;
}else{
return null;
}
} else {
throw new ClientProtocolException("Unexpected response status: " + status);
}
}
};
//返回的json对象
JSONObject responseBody = httpclient.execute(httpPost, responseHandler);
//System.out.println(responseBody);
return responseBody;
}catch (Exception e) {
e.printStackTrace();
return null;
}
}
2、有参数传递，以微信开发为例，后台访问url主动发送消息（json数据），httpClient通过设置StringEntity对象传递
/**
* 主动发送消息
* @param mess
* @return
*/
public boolean sendReqMsg(ReqBaseMessage mess){
//消息json格式
String jsonContext=mess.toJsonStr();
//System.out.println(jsonContext);
//获得token
String token=getTokenFromWx();
boolean flag=false;
try {
CloseableHttpClient httpclient = HttpClients.createDefault();
HttpPost httpPost= new HttpPost("https://qyapi.weixin.qq.com/cgi-bin/message/send?access_token="+token);
//发送json格式的数据
StringEntity myEntity = new StringEntity(jsonContext,
ContentType.create("text/plain", "UTF-8"));
//设置需要传递的数据
httpPost.setEntity(myEntity);
// Create a custom response handler
ResponseHandler<JSONObject> responseHandler = new ResponseHandler<JSONObject>() {
//对访问结果进行处理
public JSONObject handleResponse(
final HttpResponse response) throws ClientProtocolException, IOException {
int status = response.getStatusLine().getStatusCode();
if (status >= 200 && status < 300) {
HttpEntity entity = response.getEntity();
if(null!=entity){
String result= EntityUtils.toString(entity);
//根据字符串生成JSON对象
JSONObject resultObj = JSONObject.fromObject(result);
return resultObj;
}else{
return null;
}
} else {
throw new ClientProtocolException("Unexpected response status: " + status);
}
}
};
//返回的json对象
JSONObject responseBody = httpclient.execute(httpPost, responseHandler);
System.out.println(responseBody);
int result= (Integer) responseBody.get("errcode");
if(0==result){
flag=true;
}else{
flag=false;
}
httpclient.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return flag;
}
3、传递图片、文件等媒体信息，还是以微信开发为例
/**
* 文件上传到微信服务器
* @param fileType 文件类型 媒体文件类型，分别有图片（image）、语音（voice）、视频（video），普通文件(file)
* @param filePath 文件路径
* @return JSONObject
* @throws Exception
*/
public JSONObject send(String fileType, String filePath) throws Exception {
String result = null;
File file = new File(filePath);
if (!file.exists() || !file.isFile()) {
throw new IOException("文件不存在");
}
String token=getTokenFromWx();
/**
* 第一部分
*/
URL urlObj = new URL("https://qyapi.weixin.qq.com/cgi-bin/media/upload?access_token="+ token
+ "&type="+fileType+"");
HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();
con.setRequestMethod("POST"); // 以Post方式提交表单，默认get方式
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false); // post方式不能使用缓存
// 设置请求头信息
con.setRequestProperty("Connection", "Keep-Alive");
con.setRequestProperty("Charset", "UTF-8");
// 设置边界
String BOUNDARY = "----------" + System.currentTimeMillis();
con.setRequestProperty("Content-Type", "multipart/form-data; boundary="+ BOUNDARY);
// 请求正文信息
// 第一部分：
StringBuilder sb = new StringBuilder();
sb.append("--"); // 必须多两道线
sb.append(BOUNDARY);
sb.append("\r\n");
sb.append("Content-Disposition: form-data;name=\"media\";filename=\""+ file.getName() + "\"\r\n");
sb.append("Content-Type:application/octet-stream\r\n\r\n");
byte[] head = sb.toString().getBytes("utf-8");
// 获得输出流
OutputStream out = new DataOutputStream(con.getOutputStream());
// 输出表头
out.write(head);
// 文件正文部分
// 把文件已流文件的方式 推入到url中
DataInputStream in = new DataInputStream(new FileInputStream(file));
int bytes = 0;
byte[] bufferOut = new byte[1024];
while ((bytes = in.read(bufferOut)) != -1) {
out.write(bufferOut, 0, bytes);
}
in.close();
// 结尾部分
byte[] foot = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("utf-8");// 定义最后数据分隔线
out.write(foot);
out.flush();
out.close();
StringBuffer buffer = new StringBuffer();
BufferedReader reader = null;
try {
// 定义BufferedReader输入流来读取URL的响应
reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
//System.out.println(line);
buffer.append(line);
}
if(result==null){
result = buffer.toString();
}
} catch (IOException e) {
System.out.println("发送POST请求出现异常！" + e);
e.printStackTrace();
throw new IOException("数据读取异常");
} finally {
if(reader!=null){
reader.close();
}
}
JSONObject jsonObj =JSONObject.fromObject(result);
return jsonObj;
}