HttpClient的GET请求(post)请求
Posted lingtiaoti
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了HttpClient的GET请求(post)请求相关的知识,希望对你有一定的参考价值。
一。不带参数的GET请求
// 创建Httpclient对象
CloseableHttpClient httpclient = HttpClients.createDefault();
// 创建http GET请求
HttpGet httpGet = new HttpGet("http://www.baidu.com/");
CloseableHttpResponse response = null;
try {
// 执行请求
response = httpclient.execute(httpGet);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println("内容长度:"+content.length());
}
} finally {
if (response != null) {
response.close();
}
httpclient.close();
}
二。带参数的GET请求
// 创建Httpclient对象
CloseableHttpClient httpclient = HttpClients.createDefault();
// 定义请求的参数
URI uri = new URIBuilder("http://www.baidu.com/s").setParameter("wd", "java").build();
System.out.println(uri);
// 创建http GET请求
HttpGet httpGet = new HttpGet(uri);
CloseableHttpResponse response = null;
try {
// 执行请求
response = httpclient.execute(httpGet);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println(content);
}
} finally {
if (response != null) {
response.close();
}
httpclient.close();
}
三。不带参数的POST请求
// 创建Httpclient对象
CloseableHttpClient httpclient = HttpClients.createDefault();
// 创建http POST请求
HttpPost httpPost = new HttpPost("http://www.oschina.net/");
//设置请求头信息,可以伪装成浏览器访问
httpPost.setHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (Khtml, like Gecko) Chrome/68.0.3440.106 Safari/537.36");
CloseableHttpResponse response = null;
try {
// 执行请求
response = httpclient.execute(httpPost);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println(content);
}
} finally {
if (response != null) {
response.close();
}
httpclient.close();
}
四。带参数的POST请求
// 创建Httpclient对象
CloseableHttpClient httpclient = HttpClients.createDefault();
// 创建http POST请求
HttpPost httpPost = new HttpPost("http://www.oschina.net/search");
// 设置2个post参数,一个是scope、一个是q
List<NameValuePair> parameters = new ArrayList<NameValuePair>(0);
parameters.add(new BasicNameValuePair("scope", "project"));
parameters.add(new BasicNameValuePair("q", "java"));
// 构造一个form表单式的实体
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters);
// 将请求实体设置到httpPost对象中
httpPost.setEntity(formEntity);
CloseableHttpResponse response = null;
try {
// 执行请求
response = httpclient.execute(httpPost);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println(content);
}
} finally {
if (response != null) {
response.close();
}
httpclient.close();
}
五。如果考虑性能问题,可以跟创建数据库连接池的做法一样,这里创建一个连接池;例子如下:
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
// 设置最大连接数
cm.setMaxTotal(200);
// 设置每个主机地址的并发数
cm.setDefaultMaxPerRoute(20);
doGet(cm);
doGet(cm);
//这里是调用
public static void doGet(HttpClientConnectionManager cm) throws Exception {
CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build();
// 创建http GET请求
HttpGet httpGet = new HttpGet("http://www.baidu.com/");
CloseableHttpResponse response = null;
try {
// 执行请求
response = httpClient.execute(httpGet);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println("内容长度:" + content.length());
}
} finally {
if (response != null) {
response.close();
}
// 此处不能关闭httpClient,如果关闭httpClient,连接池也会销毁
// httpClient.close();
}
}
以上是关于HttpClient的GET请求(post)请求的主要内容,如果未能解决你的问题,请参考以下文章
Java学习心得之 HttpClient的GET和POST请求