【JavaWeb】HttpClient
作者：互联网
需要的依赖：
<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.13</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
参考视频：
https://www.bilibili.com/video/BV1W54y1s7BZ
1、原生JDK实现的网络请求
这个在狂神的爬虫上面有看到过原生的方式
当时还不明白这个技术其实就是后台的Ajax
@Test
public void quickStart() throws IOException {
InputStream inputStream = null;
InputStreamReader inputStreamReader = null;
BufferedReader bufferedReader = null;
try {
// 原生JDK API 发送请求
String urlString = "https://www.baidu.com/";
URL url = new URL(urlString);
URLConnection urlConnection = url.openConnection();
HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection;
httpURLConnection.setRequestMethod("GET");
httpURLConnection.setRequestProperty("aaa", "123");
inputStream = httpURLConnection.getInputStream();
inputStreamReader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
bufferedReader = new BufferedReader(inputStreamReader);
String line = null;
while (null != ( line = bufferedReader.readLine())) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
bufferedReader.close();
inputStreamReader.close();
inputStream.close();
}
}
2、使用ApacheHttpClient发送请求：
@Test
public void useHttpClient() throws IOException {
// 使用 HttpClient Get 无参请求实现
CloseableHttpClient closeableHttpClient = null;
CloseableHttpResponse closeableHttpResponse = null;
HttpEntity httpEntity = null;
try {
// 创建一个可关闭的Http客户端对象
closeableHttpClient = HttpClients.createDefault();
// 要请求的地址
String urlString = "https://www.baidu.com/";
// GET参数需要进行URL编码处理
String param1 = "orderId=21343000123324";
String param2 = "orderRemark=大三大四1王企鹅1 哇多久啊是巴西 &%……￥%";
param1 = URLEncoder.encode(param1, StandardCharsets.UTF_8.name());
param2 = URLEncoder.encode(param2, StandardCharsets.UTF_8.name());
// 根据地址创建一个Http请求对象 这里使用的是GET请求对象
// HttpGet httpGet = new HttpGet(urlString);
HttpGet httpGet = new HttpGet(urlString + "?" + param1 + "&" + param2);
// 浏览器伪装信息
httpGet.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.71 Safari/537.36 Edg/94.0.992.38");
// 防盗链设置 https://www.jianshu.com/p/0a1338db6cab
httpGet.addHeader("Referer", "https://ntp.msn.cn/");
// 客户端对象带着请求对象 执行请求发送， 返回响应对象
closeableHttpResponse = closeableHttpClient.execute(httpGet);
// 可以从响应对象获取对应的响应信息
StatusLine statusLine = closeableHttpResponse.getStatusLine();
System.out.println(statusLine); // HTTP/1.1 200 OK
// 响应不成功状态直接结束后续逻辑
if (HttpStatus.SC_OK != statusLine.getStatusCode()) return;
ProtocolVersion protocolVersion = statusLine.getProtocolVersion(); // HTTP/1.1
int major = protocolVersion.getMajor(); // 1 主版本协议号
int minor = protocolVersion.getMinor(); // 1 附属小版本协议号
String protocol = protocolVersion.getProtocol(); // HTTP
int statusCode = statusLine.getStatusCode(); // 200
String reasonPhrase = statusLine.getReasonPhrase(); // OK
Header[] allHeaders = closeableHttpResponse.getAllHeaders();
for (Header header : allHeaders) {
System.out.println("Response Header -> " + header.getName() + " : " + header.getValue());
}
// 从响应对象中获取响应实体对象
httpEntity = closeableHttpResponse.getEntity();
Header contentType = httpEntity.getContentType();
String contentTypeName = contentType.getName(); // Content-Type
String contentTypeValue = contentType.getValue(); // Content-Type: text/html;charset=utf-8
// 这个响应头不常见
// Header contentEncoding = httpEntity.getContentEncoding(); // null
// String contentEncodingName = contentEncoding.getName();
// String contentEncodingValue = contentEncoding.getValue();
// 使用实体工具类转换成字符结果
String httpEntityResult = EntityUtils.toString(httpEntity, StandardCharsets.UTF_8);
// System.out.println(httpEntityResult);
} catch (Exception exception) {
exception.printStackTrace();
} finally {
// 最后调用此方法确保资源释放
EntityUtils.consume(httpEntity);
closeableHttpResponse.close();
closeableHttpClient.close();
}
}
3、下载图片资源：
@Test
public void downloadWebPicture() throws Exception {
// 请求发送
CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
String resource = "https://img.zcool.cn/community/01088b5a052431a801204a0e253198.jpg@1280w_1l_2o_100sh.jpg";
HttpGet httpGet = new HttpGet(resource);
CloseableHttpResponse closeableHttpResponse = closeableHttpClient.execute(httpGet);
HttpEntity httpEntity = closeableHttpResponse.getEntity();
// 类型解析
Header contentType = httpEntity.getContentType();
String contentTypeValue = contentType.getValue(); // image/jpeg
String fileTypeSuffix = contentTypeValue.split("/")[1]; // jpeg
// 文件下载
byte[] bytes = EntityUtils.toByteArray(httpEntity);
String localPath = "C:\\Users\\Administrator\\Desktop\\test." + fileTypeSuffix;
OutputStream outputStream = new FileOutputStream(localPath);
outputStream.write(bytes);
// 资源释放
outputStream.close();
EntityUtils.consume(httpEntity);
closeableHttpResponse.close();
closeableHttpClient.close();
}
4、配置代理主机：
@Test
public void proxySettings() throws Exception {
CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
String target = "https://www.baidu.com/";
HttpGet httpGet = new HttpGet(target);
// 代理主机的信息 http://www.66ip.cn/
String ip = "176.121.1.81";
int port = 8181;
HttpHost httpHost = new HttpHost(ip, port);
// 创建请求配置对象
RequestConfig requestConfig = RequestConfig
.custom()
.setProxy(httpHost) // 设置代理主机的信息
.build();
// 设置请求配置
httpGet.setConfig(requestConfig);
CloseableHttpResponse closeableHttpResponse = closeableHttpClient.execute(httpGet);
HttpEntity httpEntity = closeableHttpResponse.getEntity();
Header[] allHeaders = closeableHttpResponse.getAllHeaders();
for (Header header : allHeaders) {
System.out.println("Response Header -> " + header.getName() + " : " + header.getValue());
}
String httpEntityResult = EntityUtils.toString(httpEntity, StandardCharsets.UTF_8);
System.out.println(httpEntityResult);
// 资源释放
EntityUtils.consume(httpEntity);
closeableHttpResponse.close();
closeableHttpClient.close();
}
5、设置超时相关的配置：
@Test
public void proxySettings() throws Exception {
// 请求发送
CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
String target = "https://www.baidu.com/";
HttpGet httpGet = new HttpGet(target);
// 代理主机的信息 http://www.66ip.cn/
String ip = "176.121.1.81";
int port = 8181;
HttpHost httpHost = new HttpHost(ip, port);
// 创建请求配置对象
RequestConfig requestConfig = RequestConfig
.custom()
.setProxy(httpHost)
.setConnectTimeout(5000) // 设置连接超时的上限 TCP3次握手的时限
.setSocketTimeout(3000) // 设置读取超时上限 从请求的网址中获取响应数据的间隔时限（因为并不是一次请求就完成了加载）
.setConnectionRequestTimeout(3000) // 从HttpClient连接池中获取connection对象的时限
.build();
// 设置请求配置
httpGet.setConfig(requestConfig);
CloseableHttpResponse closeableHttpResponse = closeableHttpClient.execute(httpGet);
HttpEntity httpEntity = closeableHttpResponse.getEntity();
Header[] allHeaders = closeableHttpResponse.getAllHeaders();
for (Header header : allHeaders) {
System.out.println("Response Header -> " + header.getName() + " : " + header.getValue());
}
String httpEntityResult = EntityUtils.toString(httpEntity, StandardCharsets.UTF_8);
System.out.println(httpEntityResult);
// 资源释放
EntityUtils.consume(httpEntity);
closeableHttpResponse.close();
closeableHttpClient.close();
}
6、MIME-TYPE 邮件扩展类型 与POST请求
mime-type 就是具体文件类型的前面的所属规范类型
在Tomcat里面配置的web.xml信息就可以看到所有的规范类型了
E:\apache-tomcat-8.5.70\conf\web.xml
片段：
<mime-mapping>
<extension>zirz</extension>
<mime-type>application/vnd.zul</mime-type>
</mime-mapping>
<mime-mapping>
<extension>zmm</extension>
<mime-type>application/vnd.handheld-entertainment+xml</mime-type>
</mime-mapping>
常见Content-type：
# 一般html表单提交 发送的类型 application/x-www-form-urlencoded # html上传文件规范的类型 multipart/form-data # 目前主流规范的类型 application/json
POST表单类型提交案例：
1、客户端请求代码
@Test
public void postWithFormType() throws Exception {
CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
String target = "http://localhost:8080/mvc-framework/test/testMethod2";
// 首先创建POST请求对象
HttpPost httpPost = new HttpPost(target);
// 设置表单需要提交的参数
List<NameValuePair> nvpList = new ArrayList<>();
nvpList.add(new BasicNameValuePair("username", "张三"));
nvpList.add(new BasicNameValuePair("password", "w123e21"));
// 表单类型实体对象 装填参数信息 application/x-www-form-urlencoded
UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(nvpList, Consts.UTF_8);
// 设置表单类型实体对象
httpPost.setEntity(urlEncodedFormEntity);
// 客户端执行请求发送
CloseableHttpResponse closeableHttpResponse = closeableHttpClient.execute(httpPost);
HttpEntity httpEntity = closeableHttpResponse.getEntity();
System.out.println(EntityUtils.toString(httpEntity, StandardCharsets.UTF_8));
EntityUtils.consume(httpEntity);
closeableHttpResponse.close();
closeableHttpClient.close();
}
2、服务器处理代码：
/**
*
* POST请求测试
* http://localhost:8080/mvc-framework/test/testMethod2
* @param request
* @param response
*/
// @RequestMethod(MethodType.POST)
@RequestMapping(value = "/testMethod2", methodType = MethodType.POST)
public void testMethod2(HttpServletRequest request, HttpServletResponse response) {
System.out.println("testMethod2");
ServletUtil.printAllParamByRequestMap(request);
Map<String, Object> requestAttribute = (Map<String, Object>) request.getAttribute(ServletConstants.POST_PARAM_KEY);
for (String s : requestAttribute.keySet()) {
System.out.println("postParam " + s + ": " + requestAttribute.get(s));
}
}
服务这里没有对请求做出响应，就是打印看看没有收到参数信息：
doPost detected doGet detected testMethod2 username: [张三] password: [w123e21] postParam password: w123e21 postParam username: 张三
做了两次打印的原因是第一个打印是直接调用ServletAPI实现：
基本的POST表单请求Servlet有做识别处理
public static void printAllParamByRequestMap(HttpServletRequest request) {
Map<String, String[]> parameterMap = request.getParameterMap();
for (String s : parameterMap.keySet()) {
System.out.println(s + ": " + Arrays.toString(parameterMap.get(s)));
}
}
第二次打印是从输入流中获取识别的
/**
* 从POST请求中获取参数
* @param request
* @return
* @throws Exception
*/
public static Map<String, Object> getPostParam(HttpServletRequest request) throws Exception {
// 返回参数
Map<String, Object> params = new HashMap<>();
// 获取内容格式
String contentType = request.getContentType();
if (null == contentType || "".equals(contentType)) throw new ServletException("没有设置请求头项Content-Type!!!");
else contentType = contentType.split(";")[0];
// form表单格式 表单形式可以从 ParameterMap中获取
if (ServletConstants.CONTENT_TYPE_VALUE_URL_ENCODED2.equalsIgnoreCase(contentType)) {
// 获取参数
Map<String, String[]> parameterMap = request.getParameterMap();
if (parameterMap != null) {
for (Map.Entry<String, String[]> entry : parameterMap.entrySet()) {
params.put(entry.getKey(), entry.getValue()[0]);
}
}
}
// json格式 json格式需要从request的输入流中解析获取
if (ServletConstants.CONTENT_TYPE_VALUE_JSON2.equalsIgnoreCase(contentType)) {
// 使用 commons-io中 IOUtils 类快速获取输入流内容
String paramJson = IOUtils.toString(request.getInputStream(), StandardCharsets.UTF_8);
Map parseObject = JSON.parseObject(paramJson, Map.class);
params.putAll(parseObject);
}
return params ;
}
也可以不使用 UrlEncodedFormEntity ，使用请求头设置即可
这个意思在视频里说错了，应该是这个Entity已经在Header这么处理了
// 配置Http请求头
httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
因为表单的参数还是需要放到Entity里面发送过去的
这里特意看了下Entity的实现结构：
搜寻Entity相关的时候发现这个博客写的也很好，涉及到Cookie相关的操作
https://www.cnblogs.com/licl11092/p/9075677.html
POST + JSON类型案例：
SpringMVC接受Post JSON数据时要带上 @RequestBody给方法
普通Get参数则是@RequestParam
类注解为@RestController就可以不注解@RequestBody方法
在这里我使用的是封装的一套MVC，Servlet对JSON参数是不支持的，只能从输入流自行获取
这里JSON参数采用的是StringEntity实现存储，看了源码发现默认是text/plain类型，也允许构造器自行设置类型
@Test
public void postWithFormJson() throws Exception {
CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
java.lang.String target = "http://localhost:8080/mvc-framework/test/testMethod2";
// 首先创建POST请求对象
HttpPost httpPost = new HttpPost(target);
// 设置需要提交的JSON参数 这里做简单案例，就不去下载Fastjson来转换了，自己手写一个
String jsonParam = "{ \"username\": \"张三\", \"password\": \"w123e21\" }";
// 表单类型实体对象 装填参数信息 application/x-www-form-urlencoded
StringEntity jsonEntity = new StringEntity(jsonParam , Consts.UTF_8);
// 配置Http请求头
// httpPost.addHeader("Content-Type", "application/json; charset=UTF-8");
jsonEntity.setContentType(new BasicHeader("Content-Type", "application/json; charset=UTF-8"));
// StringEntity 设置编码
jsonEntity.setContentEncoding(Consts.UTF_8.name());
// 设置JSON实体对象
httpPost.setEntity(jsonEntity);
// 客户端执行请求发送
CloseableHttpResponse closeableHttpResponse = closeableHttpClient.execute(httpPost);
HttpEntity httpEntity = closeableHttpResponse.getEntity();
System.out.println(EntityUtils.toString(httpEntity, StandardCharsets.UTF_8));
EntityUtils.consume(httpEntity);
closeableHttpResponse.close();
closeableHttpClient.close();
}
POST + 文件类型案例：
标签：httpEntity,String,closeableHttpClient,请求,new,HttpClient,closeableHttpResponse,Ja 来源： https://www.cnblogs.com/mindzone/p/15367993.html