java中的常见几种发送http请求实例
更新时间：2024年11月08日 09:14:20 作者：北极熊不在北极
在Java编程中,发送HTTP请求是一个常见需求,常用的方法有四种：HttpURLConnection、URLConnection、HttpClient以及Socket,其中,使用HttpClient方式时,需要添加额外的库支持
java常见几种发送http请求实例
<span style="font-family: Arial, Helvetica, sans-serif;">import java.io.BufferedReader;</span>
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.Socket;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
/**
* @Description:发送http请求帮助类
* @author:liuyc
* @time:2016年5月17日 下午3:25:32
*/
public class HttpClientHelper {
/**
* @Description:使用HttpURLConnection发送post请求
* @author:liuyc
* @time:2016年5月17日 下午3:26:07
*/
public static String sendPost(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> e : params.entrySet()) {
sbParams.append(e.getKey());
sbParams.append("=");
sbParams.append(e.getValue());
sbParams.append("&");
}
}
HttpURLConnection con = null;
OutputStreamWriter osw = null;
BufferedReader br = null;
// 发送请求
try {
URL url = new URL(urlParam);
con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("POST");
con.setDoOutput(true);
con.setDoInput(true);
con.setUseCaches(false);
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
if (sbParams != null && sbParams.length() > 0) {
osw = new OutputStreamWriter(con.getOutputStream(), charset);
osw.write(sbParams.substring(0, sbParams.length() - 1));
osw.flush();
}
// 读取返回内容
resultBuffer = new StringBuffer();
int contentLength = Integer.parseInt(con.getHeaderField("Content-Length"));
if (contentLength > 0) {
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用URLConnection发送post
* @author:liuyc
* @time:2016年5月17日 下午3:26:52
*/
public static String sendPost2(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> e : params.entrySet()) {
sbParams.append(e.getKey());
sbParams.append("=");
sbParams.append(e.getValue());
sbParams.append("&");
}
}
URLConnection con = null;
OutputStreamWriter osw = null;
BufferedReader br = null;
try {
URL realUrl = new URL(urlParam);
// 打开和URL之间的连接
con = realUrl.openConnection();
// 设置通用的请求属性
con.setRequestProperty("accept", "*/*");
con.setRequestProperty("connection", "Keep-Alive");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 发送POST请求必须设置如下两行
con.setDoOutput(true);
con.setDoInput(true);
// 获取URLConnection对象对应的输出流
osw = new OutputStreamWriter(con.getOutputStream(), charset);
if (sbParams != null && sbParams.length() > 0) {
// 发送请求参数
osw.write(sbParams.substring(0, sbParams.length() - 1));
// flush输出流的缓冲
osw.flush();
}
// 定义BufferedReader输入流来读取URL的响应
resultBuffer = new StringBuffer();
int contentLength = Integer.parseInt(con.getHeaderField("Content-Length"));
if (contentLength > 0) {
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
}
}
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:发送get请求保存下载文件
* @author:liuyc
* @time:2016年5月17日 下午3:27:29
*/
public static void sendGetAndSaveFile(String urlParam, Map<String, Object> params, String fileSavePath) {
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
HttpURLConnection con = null;
BufferedReader br = null;
FileOutputStream os = null;
try {
URL url = null;
if (sbParams != null && sbParams.length() > 0) {
url = new URL(urlParam + "?" + sbParams.substring(0, sbParams.length() - 1));
} else {
url = new URL(urlParam);
}
con = (HttpURLConnection) url.openConnection();
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.connect();
InputStream is = con.getInputStream();
os = new FileOutputStream(fileSavePath);
byte buf[] = new byte[1024];
int count = 0;
while ((count = is.read(buf)) != -1) {
os.write(buf, 0, count);
}
os.flush();
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
os = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
}
}
/**
* @Description:使用HttpURLConnection发送get请求
* @author:liuyc
* @time:2016年5月17日 下午3:27:29
*/
public static String sendGet(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
HttpURLConnection con = null;
BufferedReader br = null;
try {
URL url = null;
if (sbParams != null && sbParams.length() > 0) {
url = new URL(urlParam + "?" + sbParams.substring(0, sbParams.length() - 1));
} else {
url = new URL(urlParam);
}
con = (HttpURLConnection) url.openConnection();
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.connect();
resultBuffer = new StringBuffer();
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用URLConnection发送get请求
* @author:liuyc
* @time:2016年5月17日 下午3:27:58
*/
public static String sendGet2(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
BufferedReader br = null;
try {
URL url = null;
if (sbParams != null && sbParams.length() > 0) {
url = new URL(urlParam + "?" + sbParams.substring(0, sbParams.length() - 1));
} else {
url = new URL(urlParam);
}
URLConnection con = url.openConnection();
// 设置请求属性
con.setRequestProperty("accept", "*/*");
con.setRequestProperty("connection", "Keep-Alive");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 建立连接
con.connect();
resultBuffer = new StringBuffer();
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用HttpClient发送post请求
* @author:liuyc
* @time:2016年5月17日 下午3:28:23
*/
public static String httpClientPost(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
HttpClient client = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(urlParam);
// 构建请求参数
List<NameValuePair> list = new ArrayList<NameValuePair>();
Iterator<Entry<String, Object>> iterator = params.entrySet().iterator();
while (iterator.hasNext()) {
Entry<String, Object> elem = iterator.next();
list.add(new BasicNameValuePair(elem.getKey(), String.valueOf(elem.getValue())));
}
BufferedReader br = null;
try {
if (list.size() > 0) {
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, charset);
httpPost.setEntity(entity);
}
HttpResponse response = client.execute(httpPost);
// 读取服务器响应数据
resultBuffer = new StringBuffer();
br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用HttpClient发送get请求
* @author:liuyc
* @time:2016年5月17日 下午3:28:56
*/
public static String httpClientGet(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
HttpClient client = new DefaultHttpClient();
BufferedReader br = null;
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
try {
sbParams.append(URLEncoder.encode(String.valueOf(entry.getValue()), charset));
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
sbParams.append("&");
}
}
if (sbParams != null && sbParams.length() > 0) {
urlParam = urlParam + "?" + sbParams.substring(0, sbParams.length() - 1);
}
HttpGet httpGet = new HttpGet(urlParam);
try {
HttpResponse response = client.execute(httpGet);
// 读取服务器响应数据
br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String temp;
resultBuffer = new StringBuffer();
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用socket发送post请求
* @author:liuyc
* @time:2016年5月18日 上午9:26:22
*/
public static String sendSocketPost(String urlParam, Map<String, Object> params, String charset) {
String result = "";
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
Socket socket = null;
OutputStreamWriter osw = null;
InputStream is = null;
try {
URL url = new URL(urlParam);
String host = url.getHost();
int port = url.getPort();
if (-1 == port) {
port = 80;
}
String path = url.getPath();
socket = new Socket(host, port);
StringBuffer sb = new StringBuffer();
sb.append("POST " + path + " HTTP/1.1\r\n");
sb.append("Host: " + host + "\r\n");
sb.append("Connection: Keep-Alive\r\n");
sb.append("Content-Type: application/x-www-form-urlencoded; charset=utf-8 \r\n");
sb.append("Content-Length: ").append(sb.toString().getBytes().length).append("\r\n");
// 这里一个回车换行，表示消息头写完，不然服务器会继续等待
sb.append("\r\n");
if (sbParams != null && sbParams.length() > 0) {
sb.append(sbParams.substring(0, sbParams.length() - 1));
}
osw = new OutputStreamWriter(socket.getOutputStream());
osw.write(sb.toString());
osw.flush();
is = socket.getInputStream();
String line = null;
// 服务器响应体数据长度
int contentLength = 0;
// 读取http响应头部信息
do {
line = readLine(is, 0, charset);
if (line.startsWith("Content-Length")) {
// 拿到响应体内容长度
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 如果遇到了一个单独的回车换行，则表示请求头结束
} while (!line.equals("\r\n"));
// 读取出响应体数据（就是你要的数据）
result = readLine(is, contentLength, charset);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
is = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
}
return result;
}
/**
* @Description:使用socket发送get请求
* @author:liuyc
* @time:2016年5月18日 上午9:27:18
*/
public static String sendSocketGet(String urlParam, Map<String, Object> params, String charset) {
String result = "";
// 构建请求参数
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
Socket socket = null;
OutputStreamWriter osw = null;
InputStream is = null;
try {
URL url = new URL(urlParam);
String host = url.getHost();
int port = url.getPort();
if (-1 == port) {
port = 80;
}
String path = url.getPath();
socket = new Socket(host, port);
StringBuffer sb = new StringBuffer();
sb.append("GET " + path + " HTTP/1.1\r\n");
sb.append("Host: " + host + "\r\n");
sb.append("Connection: Keep-Alive\r\n");
sb.append("Content-Type: application/x-www-form-urlencoded; charset=utf-8 \r\n");
sb.append("Content-Length: ").append(sb.toString().getBytes().length).append("\r\n");
// 这里一个回车换行，表示消息头写完，不然服务器会继续等待
sb.append("\r\n");
if (sbParams != null && sbParams.length() > 0) {
sb.append(sbParams.substring(0, sbParams.length() - 1));
}
osw = new OutputStreamWriter(socket.getOutputStream());
osw.write(sb.toString());
osw.flush();
is = socket.getInputStream();
String line = null;
// 服务器响应体数据长度
int contentLength = 0;
// 读取http响应头部信息
do {
line = readLine(is, 0, charset);
if (line.startsWith("Content-Length")) {
// 拿到响应体内容长度
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 如果遇到了一个单独的回车换行，则表示请求头结束
} while (!line.equals("\r\n"));
// 读取出响应体数据（就是你要的数据）
result = readLine(is, contentLength, charset);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
is = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
}
return result;
}
/**
* @Description:读取一行数据，contentLe内容长度为0时，读取响应头信息，不为0时读正文
* @time:2016年5月17日 下午6:11:07
*/
private static String readLine(InputStream is, int contentLength, String charset) throws IOException {
List<Byte> lineByte = new ArrayList<Byte>();
byte tempByte;
int cumsum = 0;
if (contentLength != 0) {
do {
tempByte = (byte) is.read();
lineByte.add(Byte.valueOf(tempByte));
cumsum++;
} while (cumsum < contentLength);// cumsum等于contentLength表示已读完
} else {
do {
tempByte = (byte) is.read();
lineByte.add(Byte.valueOf(tempByte));
} while (tempByte != 10);// 换行符的ascii码值为10
}
byte[] resutlBytes = new byte[lineByte.size()];
for (int i = 0; i < lineByte.size(); i++) {
resutlBytes[i] = (lineByte.get(i)).byteValue();
}
return new String(resutlBytes, charset);
}
}上面4种分别可发送get和post请求的方法
- 第1种：HttpURLConnection、
- 第2种：URLConnection、
- 第3种：HttpClient、
- 第4种：Socket，朋友们要注意的是，使用第3种HttpClient时需要依赖于三个jar包，分别是：apache-httpcomponents-httpclient.jar、commons-logging-1.0.4.jar、httpcore-4.1.1.jar。
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。
相关文章
volatile用于保证多线程变量可见性与禁止重排序,适用于状态标志、单例模式等场景,但不保证原子性,相较synchronized更轻量,但需谨慎使用以避免复合操作问题,本文给大家解析Java中的volatile关键字,感兴趣的朋友一起看看吧2025-08-08
这篇文章主要介绍了java在网页上面抓取邮件地址的方法,是比较典型的Java正则匹配应用实例,具有一定的参考借鉴价值,需要的朋友可以参考下2014-11-11
这篇文章主要介绍了详解Java设计模式编程中的策略模式,策略模式强调对对象的封装使用,比如文中举的锦囊妙计的例子便很生动,需要的朋友可以参考下2016-02-02
这篇文章主要介绍了Java基础知识之Java语言概述,本文介绍了Java语言相关的基础知识、历史介绍、主要应用方向等内容,需要的朋友可以参考下2015-03-03
这篇文章主要介绍了JDK 1.8 之 Map.merge()的相关知识，本文给大家介绍的非常详细，具有一定的参考借鉴价值,需要的朋友可以参考下2019-10-10
Java 内存模型的主要目的是定义程序中各种变量的访问规则, 关注在虚拟机中把变量值存储到内存和从内存中取出变量值这样的底层细节2021-09-09
这篇文章主要介绍了Java 8 Stream操作类型及peek示例解析,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下2020-04-04
java中对象的比较equal、Comparble、Comparator的区别
本文主要介绍了java中对象的比较equal、Comparble、Comparator的区别，文中通过示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下2021-10-10
本文详细分析了SpringBoot应用内存占用过高的原因,主要包括JVM堆内存、元空间、线程栈内存和直接内存等,通过优化Tomcat线程池配置、调整JVM参数,并结合监控机制,可以有效降低应用内存占用,提高性能和稳定性,需要的朋友可以参考下2026-03-03
在进行一些自主学习的时候,发现使用maven方式创建的SpringBoot项目启动失败,最终发现是SpringBoot版本和JDK版本不对应导致的,所以本文就给大家介绍了如何查看SpringBoot和JDK版本的对应关系,需要的朋友可以参考下2024-03-03
最新评论