HttpClient的日常使用
一、代码案例
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.httpclient.*;
import org.apache.commons.httpclient.cookie.CookiePolicy;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.commons.httpclient.params.HttpMethodParams;
import java.io.*;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
/**
* @author rick
* @create 2022/2/22 15:53
*/
@Slf4j
public class HttpClientUtils {
private static String cookiee;
public static String setCookie(Cookie cookie) {
cookiee = null;
return cookiee = cookie.getValue();
}
public static String getCookie() {
return cookiee;
}
public static String doGet(String url) {
// 输入流
InputStream is = null;
BufferedReader br = null;
String result = null;
// 创建httpClient实例
HttpClient httpClient = new HttpClient();
// 设置http连接主机服务超时时间：15000毫秒
// 先获取连接管理器对象，再获取参数对象,再进行参数的赋值
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 创建一个Get方法实例对象
GetMethod getMethod = new GetMethod(url);
// 设置get请求超时为60000毫秒
getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
// 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反
getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));
try {
// 执行Get方法
int statusCode = httpClient.executeMethod(getMethod);
// 判断返回码
if (statusCode != HttpStatus.SC_OK) {
// 如果状态码返回的不是ok,说明失败了,打印错误信息
System.err.println("Method faild: " + getMethod.getStatusLine());
} else {
// 通过getMethod实例，获取远程的一个输入流
is = getMethod.getResponseBodyAsStream();
// 包装输入流
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
// 读取封装的输入流
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp).append("\r\n");
}
result = sbf.toString();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 释放连接
getMethod.releaseConnection();
}
return result;
}
public static String doGetFile(String url, OutputStream outputStream) {
// 输入流
InputStream imageStream = null;
BufferedReader br = null;
String result = null;
// 创建httpClient实例
HttpClient httpClient = new HttpClient();
// 设置http连接主机服务超时时间：15000毫秒
// 先获取连接管理器对象，再获取参数对象,再进行参数的赋值
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 创建一个Get方法实例对象
GetMethod getMethod = new GetMethod(url);
// 设置get请求超时为60000毫秒
getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
// 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反
getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));
try {
// 执行Get方法
int statusCode = httpClient.executeMethod(getMethod);
// 判断返回码
if (statusCode != HttpStatus.SC_OK) {
// 如果状态码返回的不是ok,说明失败了,打印错误信息
System.err.println("Method faild: " + getMethod.getStatusLine());
} else {
// 通过getMethod实例，获取远程的一个输入流
imageStream = getMethod.getResponseBodyAsStream();
// 输出图片内容
byte[] b = new byte[1024];
int len;
while ((len = imageStream.read(b, 0, 1024)) != -1) {
outputStream.write(b, 0, len);
}
}
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != imageStream) {
try {
imageStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 释放连接
getMethod.releaseConnection();
}
return result;
}
public static String doPost(String url, Map<String, Object> paramMap) {
HttpClientUtils.cookiee = null;
// 获取输入流
InputStream is = null;
BufferedReader br = null;
String result = null;
// 创建httpClient实例对象
HttpClient httpClient = new HttpClient();
httpClient.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);
// 设置httpClient连接主机服务器超时时间：15000毫秒
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 创建post请求方法实例对象
PostMethod postMethod = new PostMethod(url);
// 设置post请求超时时间
postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
NameValuePair[] nvp = null;
// 判断参数map集合paramMap是否为空
if (null != paramMap && paramMap.size() > 0) {// 不为空
// 创建键值参数对象数组，大小为参数的个数
nvp = new NameValuePair[paramMap.size()];
// 循环遍历参数集合map
Set<Entry<String, Object>> entrySet = paramMap.entrySet();
// 获取迭代器
Iterator<Entry<String, Object>> iterator = entrySet.iterator();
int index = 0;
while (iterator.hasNext()) {
Entry<String, Object> mapEntry = iterator.next();
// 从mapEntry中获取key和value创建键值对象存放到数组中
try {
nvp[index] = new NameValuePair(mapEntry.getKey(),
new String(mapEntry.getValue().toString().getBytes("UTF-8"), "UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
index++;
}
}
// 判断nvp数组是否为空
if (null != nvp && nvp.length > 0) {
// 将参数存放到requestBody对象中
postMethod.setRequestBody(nvp);
}
// 执行POST方法
try {
int statusCode = httpClient.executeMethod(postMethod);
// 判断是否成功
if (statusCode != HttpStatus.SC_OK) {
log.error("獲取 cookie 失败 ！！Method faild: " + postMethod.getStatusLine());
}
// 判断是否成功
if (statusCode == HttpStatus.SC_OK) {
Cookie[] cookies = httpClient.getState().getCookies();
setCookie(cookies[0]);
}
// 获取远程返回的数据
is = postMethod.getResponseBodyAsStream();
// 封装输入流
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp).append("\r\n");
}
result = sbf.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 释放连接
postMethod.releaseConnection();
}
return result;
}
/**
* 针对对方为 @RequestBody 的这种rest风格的时候，我们才用这个JSON方式去请求。 案例:
*
* @param url
* @param paramMap
* @return
*/
public static String doPostJson(String url, Map<String, Object> paramMap) {
// 获取输入流
InputStream is = null;
BufferedReader br = null;
String result = null;
// 创建httpClient实例对象
HttpClient httpClient = new HttpClient();
httpClient.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);
// 设置httpClient连接主机服务器超时时间：15000毫秒
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 创建post请求方法实例对象
PostMethod postMethod = new PostMethod(url);
// 设置post请求超时时间
postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
NameValuePair[] nvp = null;
// 判断参数map集合paramMap是否为空
if (null != paramMap && paramMap.size() > 0) {// 不为空
// 创建键值参数对象数组，大小为参数的个数
nvp = new NameValuePair[paramMap.size()];
// 循环遍历参数集合map
Set<Entry<String, Object>> entrySet = paramMap.entrySet();
// 获取迭代器
Iterator<Entry<String, Object>> iterator = entrySet.iterator();
int index = 0;
while (iterator.hasNext()) {
Entry<String, Object> mapEntry = iterator.next();
// 从mapEntry中获取key和value创建键值对象存放到数组中
try {
nvp[index] = new NameValuePair(mapEntry.getKey(),
new String(mapEntry.getValue().toString().getBytes("UTF-8"), "UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
index++;
}
}
// 执行POST方法
try {
// 判断nvp数组是否为空
if (null != nvp && nvp.length > 0) {
// 将参数存放到requestBody对象中
postMethod.setRequestBody(nvp);
postMethod.addRequestHeader("Accept", "application/json");
postMethod.addRequestHeader("Content-Type", "application/json;charset=utf-8;");
postMethod.setRequestEntity(new StringRequestEntity(nvp[0].getValue(), "application/json", "UTF-8"));
}
int statusCode = httpClient.executeMethod(postMethod);
// 判断是否成功
if (statusCode != HttpStatus.SC_OK) {
log.error("獲取 cookie 失败 ！！Method faild: " + postMethod.getStatusLine());
}
// 获取远程返回的数据
is = postMethod.getResponseBodyAsStream();
// 封装输入流
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp).append("\r\n");
}
result = sbf.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 释放连接
postMethod.releaseConnection();
}
return result;
}
}
二、案例讲解：
1、doPostJson方法 与@RequestBody请求体
比如我这里需要发起请求：
/**
* 审批-完成该节点任务
* @return
*/
@RequestMapping(value = "/completeTask/{taskId}", method = RequestMethod.POST)
public void getMsg(@PathVariable("taskId") String taskId, @RequestBody(required = false) Map<String, Object> variables) throws IOException {
//http://localhost:9001 可以作为配置项，后期换域名端口生产等都可以直接替换
String url = "http://localhost:9001/task/manage/completeTask/" + taskId;
variables.put("userName","admin");
// {"deptleaderapprove":"true","hr":"admin","comment":""}
Map<String,Object> hashMap = new HashMap<>(1);
hashMap.put("variables",JSON.toJSONString(variables));
HttpClientUtils.doPostJson(url, hashMap);
}
// 第二种 就是增加入参@RequestBody String userName：
/**
* 审批-完成该节点任务
* @return
*/
@RequestMapping(value = "/completeTask/{taskId}", method = RequestMethod.POST)
public void getMsg(@PathVariable("taskId") String taskId, @RequestBody(required = false) Map<String, Object> variables) throws IOException {
//http://localhost:9001 可以作为配置项，后期换域名端口生产等都可以直接替换
String url = "http://localhost:9001/task/manage/oaCompleteTask/" + taskId;
// variables.put("userName","admin");
// {"deptleaderapprove":"true","hr":"admin","comment":""}
Map<String,Object> hashMap = new HashMap<>(1);
hashMap.put("variables",JSON.toJSONString(variables));
// 主要是增加这里********************
hashMap.put("userName","admin");
HttpClientUtils.doPostJson(url, hashMap);
}
对应服务方：
@ApiOperation("办理一个用户任务")
@RequestMapping(value = "/completeTask/{taskId}", method = RequestMethod.POST)
@ResponseBody
public AjaxResult completeTask(@PathVariable("taskId") String taskId, @RequestBody(required = false) Map<String, Object> variables) {
SysUser user = getSysUser();
String username = user.getLoginName();
return success();
}
// 第二种增加了入参： @RequestBody String userName
@ApiOperation("OA办理一个用户任务")
@RequestMapping(value = "/oaCompleteTask/{taskId}", method = RequestMethod.POST)
@ResponseBody
public AjaxResult oaCompleteTask(@PathVariable("taskId") String taskId, @RequestBody String userName, @RequestBody(required = false) Map<String, Object> variables) {
taskService.setAssignee(taskId, userName);
return null;
2、普通post请求非JSON格式，采用表单格式提交
请求方
//入参 获取其他服务的我的待办
Map<String, Object> paramMap = new HashMap<>(2);
paramMap.put("pageSize", 10);
paramMap.put("pageNum", 1);
paramMap.put("userName", "admin");
String url = "http://localhost:9001/task/manage/mylistByUser";
String s = HttpClientUtils.doPost(url, paramMap);
服务方：
/**
* 查询我的待办任务列表
*/
@ApiOperation("查询我的待办任务列表")
@PostMapping("/mylistByUser")
@ResponseBody
// ynkj 待办
public TableDataInfo mylistByUser(TaskInfo param) {
return rspData;
}
3、GET请求
请求方
/**
* 查询审批流的 文件
* @return
*/
@RequestMapping(value = "/traceProcess/{processInstanceId}", method = RequestMethod.GET)
public void getMsg(@PathVariable String processInstanceId, HttpServletResponse response) throws IOException {
//http://localhost:9001 可以作为配置项，后期换域名端口生产等都可以直接替换
String url = "http://localhost:9001/flow/monitor/traceProcess/" + processInstanceId;
HttpClientUtils.doGetFile(url, response.getOutputStream());
}
服务方：
@ApiOperation("流程图进度追踪,已结束标红，运行中标绿")
@RequestMapping(value = {"/traceProcess/{processInstanceId}"}, method = RequestMethod.GET)
public void traceprocess(@PathVariable String processInstanceId, HttpServletResponse response) throws IOException {
activitiTracingChart.generateFlowChart(processInstanceId, response.getOutputStream());
}
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