Java调用Http/Https接口(2)--HttpURLConnection/HttpsURLConnection调用Http/Https接口
HttpURLConnection是JDK自身提供的网络类，不需要引入额外的jar包。文中所使用到的软件版本：Java 1.8.0_191。
1、服务端
2、调用Http接口
2.1、GET请求
public static void get() {
try {
String requestPath = "http://localhost:8080/demo/httptest/getUser?userId=1000&userName=" + URLEncoder.encode("李白", "utf-8");
URL url = new URL(requestPath);
//设置代理
//InetSocketAddress addr = new InetSocketAddress("127.0.0.1", 8888);
//Proxy proxy = new Proxy(Proxy.Type.HTTP, addr);
//connection = (HttpURLConnection)url.openConnection(proxy);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("GET返回结果：" + back);
} else {
System.out.println("GET请求状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.2、POST请求(发送键值对数据）
public static void post() {
try {
String requestPath = "http://localhost:8080/demo/httptest/getUser";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.connect();
String param = "userId=1000&userName=李白";
bytesToOutputStream(param.getBytes(), connection.getOutputStream());
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("POST返回结果：" + back);
} else {
System.out.println("POST返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.3、POST请求(发送JSON数据）
public static void post2() {
try {
String requestPath = "http://localhost:8080/demo/httptest/addUser";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setRequestProperty("Content-type", "application/json");
connection.connect();
String param = "{\"userId\": \"1001\",\"userName\":\"杜甫\"}";
bytesToOutputStream(param.getBytes(), connection.getOutputStream());
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("POST2返回结果：" + back);
} else {
System.out.println("POST2返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.4、上传文件
public static void upload() {
try {
String requestPath = "http://localhost:8080/demo/httptest/upload";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setRequestProperty("Content-type", "file/*");
connection.connect();
FileInputStream fileInputStream = new FileInputStream("d:/a.jpg");
inputStreamToOutputStream(fileInputStream, connection.getOutputStream());
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("upload返回结果：" + back);
} else {
System.out.println("upload返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.5、上传文件及发送键值对数据
2.5.1、分析数据结构
通过抓包工具分析页面表单上传文件的过程，可以看出传输数据的结构：
2.5.2、根据分析出的数据结构编写代码
public static void multi() {
String BOUNDARY = java.util.UUID.randomUUID().toString();
String TWO_HYPHENS = "--";
String LINE_END = "\r\n";
FileInputStream in = null;
try {
String requestPath = "http://localhost:8080/demo/httptest/multi";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestProperty("Content-type", "multipart/form-data; BOUNDARY=" + BOUNDARY);
connection.connect();
StringBuffer sb = new StringBuffer();
//封装键值对数据1
sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
sb.append("Content-Disposition: form-data; name=\"param1\"").append(LINE_END);
sb.append(LINE_END);
sb.append("参数1").append(LINE_END);
//封装键值对数据2
sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
sb.append("Content-Disposition: form-data; name=\"param2\"").append(LINE_END);
sb.append(LINE_END);
sb.append("参数2").append(LINE_END);
//封装文件数据
sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
sb.append("Content-Disposition: form-data; name=\"file\"; filename=\"a.jpg\"").append(LINE_END);
sb.append("Content-Type: file/*").append(LINE_END);
sb.append(LINE_END);
bytesToOutputStream(sb.toString().getBytes(), connection.getOutputStream());
in = new FileInputStream("d:/a.jpg");
inputStreamToOutputStream(in, connection.getOutputStream());
//写入标记结束位
String end = (LINE_END + TWO_HYPHENS + BOUNDARY + TWO_HYPHENS + LINE_END);
bytesToOutputStream(end.getBytes(), connection.getOutputStream());
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("multi返回结果：" + back);
} else {
System.out.println("multi返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
FileUtil.close(in);
}
}
2.5.3、上传文件方法变通
这种方式上传文件完全是模拟页面的提交行为来编码的，比较繁琐。可以把文件转成字符串，然后通过键值对传给服务端，服务端执行相反的过程来存储文件：
客户端：文件-> 字节数组->Base64字符串
服务端：Base64字符串-> 字节数组->文件
按照这种方式来实现应该比较容易，这里就不演示了。
2.6、下载文件
public static void download() {
FileOutputStream out = null;
try {
String requestPath = "http://localhost:8080/demo/httptest/download";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.connect();
System.out.println("download返回状态码：" + connection.getResponseCode());
String contentDisposition = connection.getHeaderField("Content-Disposition");//attachment; filename="a.jpg"
String fileName = "none";
if (contentDisposition != null && contentDisposition.indexOf("filename") > -1) {
fileName = contentDisposition.substring(contentDisposition.indexOf("\"") + 1, contentDisposition.length() - 1);
fileName = java.net.URLDecoder.decode(fileName, "utf-8");
}
out = new FileOutputStream("d:/temp/dowload_" + System.currentTimeMillis() + "_" + fileName);
inputStreamToOutputStream(connection.getInputStream(), out);
} catch (Exception e) {
e.printStackTrace();
} finally {
FileUtil.close(out);
}
}
2.7、完整例子
package com.inspur.demo.http.client; import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
//import java.net.InetSocketAddress;
//import java.net.Proxy;
import java.net.URL;
import java.net.URLEncoder; import com.inspur.demo.common.util.FileUtil; /**
*
* 通过HttpURLConnection调用Http接口
*
*/
public class HttpURLConnectionCase {
/**
* GET请求
*/
public static void get() {
try {
String requestPath = "http://localhost:8080/demo/httptest/getUser?userId=1000&userName=" + URLEncoder.encode("李白", "utf-8");
URL url = new URL(requestPath);
//设置代理
//InetSocketAddress addr = new InetSocketAddress("127.0.0.1", 8888);
//Proxy proxy = new Proxy(Proxy.Type.HTTP, addr);
//connection = (HttpURLConnection)url.openConnection(proxy); HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("GET");
connection.connect(); if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("GET返回结果：" + back);
} else {
System.out.println("GET请求状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* POST请求，发送键值对数据
*/
public static void post() {
try {
String requestPath = "http://localhost:8080/demo/httptest/getUser";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.connect(); String param = "userId=1000&userName=李白";
bytesToOutputStream(param.getBytes(), connection.getOutputStream()); if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("POST返回结果：" + back);
} else {
System.out.println("POST返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* POST请求，发送json格式数据
*/
public static void post2() {
try {
String requestPath = "http://localhost:8080/demo/httptest/addUser";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setRequestProperty("Content-type", "application/json");
connection.connect(); String param = "{\"userId\": \"1001\",\"userName\":\"杜甫\"}";
bytesToOutputStream(param.getBytes(), connection.getOutputStream()); if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("POST2返回结果：" + back);
} else {
System.out.println("POST2返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 上传文件
*/
public static void upload() {
try {
String requestPath = "http://localhost:8080/demo/httptest/upload";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setRequestProperty("Content-type", "file/*");
connection.connect(); FileInputStream fileInputStream = new FileInputStream("d:/a.jpg");
inputStreamToOutputStream(fileInputStream, connection.getOutputStream()); if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("upload返回结果：" + back);
} else {
System.out.println("upload返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 上传文件及发送键值对数据
*/
public static void multi() {
String BOUNDARY = java.util.UUID.randomUUID().toString();
String TWO_HYPHENS = "--";
String LINE_END = "\r\n";
FileInputStream in = null;
try {
String requestPath = "http://localhost:8080/demo/httptest/multi";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestProperty("Content-type", "multipart/form-data; BOUNDARY=" + BOUNDARY);
connection.connect(); StringBuffer sb = new StringBuffer();
//封装键值对数据1
sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
sb.append("Content-Disposition: form-data; name=\"param1\"").append(LINE_END);
sb.append(LINE_END);
sb.append("参数1").append(LINE_END); //封装键值对数据2
sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
sb.append("Content-Disposition: form-data; name=\"param2\"").append(LINE_END);
sb.append(LINE_END);
sb.append("参数2").append(LINE_END); //封装文件数据
sb.append(TWO_HYPHENS).append(BOUNDARY).append(LINE_END);
sb.append("Content-Disposition: form-data; name=\"file\"; filename=\"a.jpg\"").append(LINE_END);
sb.append("Content-Type: file/*").append(LINE_END);
sb.append(LINE_END); bytesToOutputStream(sb.toString().getBytes(), connection.getOutputStream()); in = new FileInputStream("d:/a.jpg");
inputStreamToOutputStream(in, connection.getOutputStream()); //写入标记结束位
String end = (LINE_END + TWO_HYPHENS + BOUNDARY + TWO_HYPHENS + LINE_END);
bytesToOutputStream(end.getBytes(), connection.getOutputStream()); if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
byte[] b = getBytesFromInputStream(connection.getInputStream());
String back = new String(b);
System.out.println("multi返回结果：" + back);
} else {
System.out.println("multi返回状态码：" + connection.getResponseCode());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
FileUtil.close(in);
}
} /**
* 下载文件
*/
public static void download() {
FileOutputStream out = null;
try {
String requestPath = "http://localhost:8080/demo/httptest/download";
URL url = new URL(requestPath);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("POST");
connection.connect();
System.out.println("download返回状态码：" + connection.getResponseCode());
String contentDisposition = connection.getHeaderField("Content-Disposition");//attachment; filename="a.jpg"
String fileName = "none";
if (contentDisposition != null && contentDisposition.indexOf("filename") > -1) {
fileName = contentDisposition.substring(contentDisposition.indexOf("\"") + 1, contentDisposition.length() - 1);
fileName = java.net.URLDecoder.decode(fileName, "utf-8");
}
out = new FileOutputStream("d:/temp/dowload_" + System.currentTimeMillis() + "_" + fileName);
inputStreamToOutputStream(connection.getInputStream(), out);
} catch (Exception e) {
e.printStackTrace();
} finally {
FileUtil.close(out);
}
} /**
* 从输入流获取数据
* @param in
* @return
* @throws IOException
*/
private static byte[] getBytesFromInputStream(InputStream in) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] b = new byte[1024];
int len;
while ((len = in.read(b)) != -1) {
out.write(b, 0, len);
}
byte[] bytes = out.toByteArray();
out.close();
return bytes;
} /**
* 把字节数组写入输出流
* @param bytes
* @param out
* @throws IOException
*/
private static void bytesToOutputStream(byte[] bytes, OutputStream out) throws IOException {
ByteArrayInputStream in = new ByteArrayInputStream(bytes);
byte[] b = new byte[1024];
int len;
while ((len = in.read(b)) != -1) {
out.write(b, 0, len);
}
out.flush();
in.close();
} /**
* 从输入流读取数据并写入输出流
* @param out
* @param bytes
* @throws IOException
*/
private static void inputStreamToOutputStream(InputStream in, OutputStream out) throws IOException {
byte[] b = new byte[1024];
int len;
while ((len = in.read(b)) != -1) {
out.write(b, 0, len);
}
out.flush();
} public static void main(String[] args) {
get();
post();
post2();
upload();
multi();
download();
}
}
3、调用Https接口
调用Https接口需要用HttpsURLConnection，与调用Http接口不一样的部分主要在设置ssl部分，下面用GET请求来演示ssl的设置，其他调用方式类似。
3.1、导入cer证书
对于自定义证书的网站，需把证书用java自带的工具keytool导入本地，如导入到d:/temp目录下
cd d:/temp
keytool -import -alias aa -keystore cacerts -file aa.cer -trustcacerts
如果当前目录已有cacerts证书库，则需输入密码；如果没有则需设置密码，会在当前目录下生成cacerts证书库。
也可以不导入，使用默认实现的DefaultTrustManager，信任所有，将导致不安全。
3.2、示例
package com.inspur.demo.http.client; import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.security.KeyStore;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate; import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager; import com.inspur.demo.common.util.FileUtil; /**
* 通过HttpsURLConnection调用Https接口
*/
public class HttpsURLConnectionCase {
public static void main(String[] args) {
try {
/*
* 请求有权威证书的地址
*/
String requestPath = "https://www.baidu.com/";
HttpsURLConnection connection = getHttpsURLConnection(requestPath, "GET");
String result = new String(getBytesFromInputStream(connection.getInputStream()));
System.out.println("GET1返回结果：" + result); /*
* 请求自定义证书的地址
*/
//获取信任库
KeyStore trustStore = getkeyStore("jks", "d:/temp/cacerts", "123456"); //不需客户端证书
requestPath = "https://x.x.x.x:9010/zsywservice";
connection = getHttpsURLConnection(requestPath, "GET", null, null, trustStore);
result = new String(getBytesFromInputStream(connection.getInputStream()));
System.out.println("GET2返回结果：" + result); //需客户端证书
requestPath = "https://x.x.x.x:9016/zsywservice";
KeyStore keyStore = getkeyStore("pkcs12", "d:/client.p12", "123456");
connection = getHttpsURLConnection(requestPath, "GET", keyStore, "123456", trustStore);
result = new String(getBytesFromInputStream(connection.getInputStream()));
System.out.println("GET3返回结果：" + result);
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 获取证书
* @return
*/
private static KeyStore getkeyStore(String type, String filePath, String password) {
KeyStore keySotre = null;
FileInputStream in = null;
try {
keySotre = KeyStore.getInstance(type);
in = new FileInputStream(new File(filePath));
keySotre.load(in, password.toCharArray());
} catch (Exception e) {
e.printStackTrace();
} finally {
FileUtil.close(in);
}
return keySotre;
} private static HttpsURLConnection getHttpsURLConnection(String uri, String method) throws Exception {
URL url = new URL(uri);
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
connection.setRequestMethod(method);
connection.setDoInput(true);
connection.setDoOutput(true);
return connection;
} /**
* 获取连接
* @param uri
* @param method
* @param keyStore
* @param trustStore
* @return
* @throws Exception
*/
private static HttpsURLConnection getHttpsURLConnection(String uri, String method, KeyStore keyStore, String keyStorePassword, KeyStore trustStore) throws Exception {
KeyManager[] keyManagers = null;
TrustManager[] trustManagers = null;
if (keyStore != null) {
KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("SunX509");
keyManagerFactory.init(keyStore, keyStorePassword.toCharArray());
keyManagers = keyManagerFactory.getKeyManagers();
}
if (trustStore != null) {
TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance("SunX509");
trustManagerFactory.init(trustStore);
trustManagers = trustManagerFactory.getTrustManagers();
} else {
trustManagers = new TrustManager[] { new DefaultTrustManager()};
} //设置服务端支持的协议
SSLContext context = SSLContext.getInstance("TLSv1.2");
context.init(keyManagers, trustManagers, null);
SSLSocketFactory sslFactory = context.getSocketFactory(); URL url = new URL(uri);
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
connection.setSSLSocketFactory(sslFactory);
//验证URL的主机名和服务器的标识主机名是否匹配
connection.setHostnameVerifier(new HostnameVerifier() {
@Override
public boolean verify(String hostname, SSLSession session) {
//if ("xxx".equals(hostname)) {
// return true;
//} else {
// return false;
//}
return true;
}
});
connection.setRequestMethod(method);
connection.setDoInput(true);
connection.setDoOutput(true);
return connection;
} /**
* 默认的TrustManager实现，不安全
*/
private static final class DefaultTrustManager implements X509TrustManager {
@Override
public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
} @Override
public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
} @Override
public X509Certificate[] getAcceptedIssuers() {
return null;
}
} /**
* 从输入流获取数据
* @param in
* @return
* @throws IOException
*/
private static byte[] getBytesFromInputStream(InputStream in) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] b = new byte[1024];
int len;
while ((len = in.read(b)) != -1) {
out.write(b, 0, len);
}
byte[] bytes = out.toByteArray();
out.close();
return bytes;
}
}
3.2、Received fatal alert:handshake_failure
出现这种这种问题的一种情况是由于客户端使用的协议，服务端不支持造成的；修改为服务端所支持的协议即可。在getHttpsURLConnection方法中修改：
SSLContext context = SSLContext.getInstance("TLSv1.2");
可选的协议参数有：SSL、SSLv2、SSLv3、TLS、TLSv1、TLSv1.1、TLSv1.2；TLS是SSL标准化的产物，故现在基本只使用TLS相关的参数。
可以用linux的curl命令来测试服务端支持哪些协议：
curl -k https://x.x.x.x:9016/zsywservice --tlsv1.2 -v
可选协议有：--tlsv1、--tlsv1.0、--tlsv1.1、--tlsv1.2、--tlsv1.3
如果出现如下信息，则表示不支持：
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