HTTP协议可以说是WEB项目中最常用的协议了，项目开发中一般使用Httpclient进行HTTP接口的请求，Httpclient封装了HTTP协议的细节，如果不用Httpclient如何进行HTTP请求呢，下面是一个简单的实现HTTP协议的小程序：
主要类SimpleHttpGet：
package com.zws.http;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
*
* @author wensh.zhu 2017-03-11
请求报文格式：
GET /greeting.do?name=jack HTTP/1.1\r\n
Host: localhost:8011\r\n
Connection: keep-alive\r\n
Cache-Control: max-age=0\r\n
Upgrade-Insecure-Requests: 1\r\n
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36\r\n
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*此处为斜线(/)*;q=0.8\r\n
Accept-Encoding: gzip, deflate, sdch, br\r\n
Accept-Language: zh-CN,zh;q=0.8\r\n
\r\n
响应报文格式：
一次性响应：
HTTP/1.1 200 OK\r\n
Server: Apache-Coyote/1.1\r\n
Set-Cookie: JSESSIONID=54B11BE01CD7983726618546CF4521E1; Path=/Newer/; HttpOnly\r\n
Content-Type: text/html;charset=UTF-8\r\n
Content-Length: 4\r\n//报文正文长度
Date: Sat, 11 Mar 2017 15:16:10 GMT\r\n
\r\n//报头结束
abcd//正文
分块响应:
HTTP/1.1 200 OK\r\n
Content-Type: application/json;charset=UTF-8\r\n
Transfer-Encoding: chunked\r\n//表示分块响应
Date: Sat, 11 Mar 2017 14:19:25 GMT\r\n
\r\n //报头结束
8\r\n//十六进制长度
abcdefgh\r\n//正文
2\r\n
ab\r\n
0\r\n//结束
*/
public class SimpleHttpGet {
private int connectTimeout = 2000;//链接超时时间
private int readTimeout = 5000;//读超时时间
private String host;
private int port = 80;
private static String DEF_CHARSET = "UTF-8";
private String resourcePath = "/";//资源路径
private String reqLine;
private Map<String, String> headers = new HashMap<String, String>();
public SimpleHttpGet(String uri) {
initRequestHeader();
parseRequestLine(uri);
}
public SimpleHttpGet(String uri, int connectTimeout, int readTimeOut) {
initRequestHeader();
parseRequestLine(uri);
this.connectTimeout = connectTimeout;
this.readTimeout = readTimeOut;
}
/**
* 解析出IP地址、端口以及请求资源
* @param uri
* @throws UnsupportedEncodingException
*/
private void parseRequestLine(String uri) {
String url = uri;
if (url == null || url.length() == 0)
throw new NullPointerException("uri can not be null");
if (!url.startsWith("http"))
url = "http://" + uri;
String[] parts = url.split("//");
String mainPart = parts[1];
int ipFlag = mainPart.indexOf("/");
if (ipFlag != -1) {
String ipPort = mainPart.substring(0, ipFlag);
String[] ipParts = ipPort.split(":");
if (ipParts.length > 1) {
host = ipParts[0];
String portStr = ipParts[1];
if (portStr != null && portStr.length() > 0)
port = Integer.parseInt(portStr);
} else {
host = ipPort;
}
String resourcePart = mainPart.substring(ipFlag);
resourcePath = resourcePart;
} else {
host = mainPart;
}
String hostVal = host;
if (port != 80) hostVal += ":" + port;
headers.put("Host", hostVal);
reqLine = "GET " + resourcePath + " HTTP/1.1\r\n";
}
/**
* 初始化请求头
*/
private void initRequestHeader() {
headers.put("Connection", "keep-alive");
headers.put("Upgrade-Insecure-Requests", "1");
headers.put("User-Agent", "Java client");
headers.put("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
headers.put("Accept-Encoding", "gzip");
headers.put("Accept-Language", "zh-CN,zh");
headers.put("Content-Type", "text/html;charset=utf-8");
}
public void setHeader(String key, String value) {
headers.put(key, value);
}
public RespMsg req() {
RespMsg msg = null;
Socket socket = null;
OutputStream out = null;
InputStream in = null;
try {
SocketAddress endpoint = new InetSocketAddress(host, port);
socket = new Socket();
socket.connect(endpoint, connectTimeout);
socket.setSoTimeout(readTimeout);
out = socket.getOutputStream();
write(out);
in = socket.getInputStream();
msg = read(in);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (out != null)
out.close();
if (in != null)
in.close();
if (socket != null)
socket.close();
} catch (Exception e2) {
e2.printStackTrace();
}
}
return msg;
}
private void write(OutputStream out) throws IOException {
String reqBody = reqLine;
Iterator<String> itor = headers.keySet().iterator();
while (itor.hasNext()) {
String key = itor.next();
String val = headers.get(key);
String header = key + ":" + val + "\r\n";
reqBody += header;
}
reqBody += "\r\n";
System.out.println(reqBody);
out.write(reqBody.getBytes());
}
private RespMsg read(InputStream in) throws IOException {
RespMsg respMsg = new RespMsg();
byte[] heads = HttpStreamReader.readHeaders(in);
String headStr = new String(heads);
String[] lines = headStr.split("\r\n");
RespHeader resp = new RespHeader();
if (lines.length > 0)
resp.setRespLine(lines[0]);
for (int i = 1; i < lines.length; i++)
resp.addHeader(lines[i]);
String body = null;
if (resp.isChunked()) {
body = readChunked(in);
} else {
int bodyLen = resp.getContentLenth();
byte[] bodyBts = new byte[bodyLen];
in.read(bodyBts);
body = new String(bodyBts, DEF_CHARSET);
}
respMsg.setRespBody(body);
String respLine = resp.getRespLine();
respMsg.setRespCodeMsg(respLine);
return respMsg;
}
/**
* 分块读取
* @param in
* @return
* @throws IOException
*/
private static String readChunked(InputStream in) throws IOException {
String content = "";
String lenStr = "0";
while (!(lenStr = new String(HttpStreamReader.readLine(in))).equals("0")) {
int len = Integer.valueOf(lenStr.toUpperCase(),16);//长度16进制表示
byte[] cnt = new byte[len];
in.read(cnt);
content += new String(cnt, "UTF-8");
in.skip(2);
}
return content;
}
}
三个辅助类：
HttpStreamReader类：
package com.zws.http;import java.io.IOException;import java.io.InputStream;import java.util.Arrays;/** * * @author wensh.zhu 2017-03-11 * */public class HttpStreamReader {/** * 行结束标识，\r\n(13,10) */public static final byte[] LINE_END = {13, 10};/** * 响应头结束标识，\r\n\r\n(13,10,13,10) */public static final byte[] ALL_END = {13, 10, 13, 10};public static byte[] getBytes(InputStream in) throws IOException {byte[] buffer = new byte[1024];int len = 0;int ind = 0;while ((len = in.read(buffer, ind, buffer.length - ind)) > 0){if (len == buffer.length - ind) {//full int l = buffer.length;byte[] newBuffer = new byte[l * 2];System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);buffer = newBuffer;ind = l;} else {ind += len;}}byte[] result = new byte[ind];System.arraycopy(buffer, 0, result, 0, ind);return result;}public static byte[] readHeaders(InputStream in) throws IOException {return read(in, ALL_END);}public static byte[] readLine(InputStream in) throws IOException {return read(in, LINE_END);}public static byte[] read(InputStream in, byte[] endFlag) throws IOException {byte[] buffer = new byte[1024];int ind = 0;int bt = 0;while ((bt = in.read()) != -1){ buffer[ind] = (byte)bt;if (isTailEqual(buffer, ind, endFlag))break;ind ++;}int newLen = ind + 1 - endFlag.length;byte[] result = new byte[newLen];System.arraycopy(buffer, 0, result, 0, newLen);return result;}/** * bts的后ends.length个字节是否和ends相等 * @param bts * @param ends * @return */public static boolean isTailEqual(byte[] bts, int endIndex, byte[] ends){int btsLen = endIndex + 1;int endLen = ends.length;if (btsLen < endLen) return false;int tailFrom = btsLen - endLen;int tailTo = btsLen;byte[] tail = Arrays.copyOfRange(bts, tailFrom, tailTo);for (int i = 0; i < endLen; i++) if (tail[i] != ends[i]) return false;return true;}}
RespHeader类：
package com.zws.http;import java.util.HashMap;import java.util.Map;import java.util.Set;/** * * @author wensh.zhu 2017-03-11 * */public class RespHeader {private String respLine;private Map<String, String> headers = new HashMap<String, String>();public void addHeader(String head) {if (head == null || head.length() < 1)return;String[] nameVal = head.split(":");String name = nameVal[0], val = null;if (nameVal.length > 1)val = nameVal[1].replaceFirst(" ", "");headers.put(name, val);}public String getHeader(String header) {return headers.get(header);}public int getContentLenth() {int len = 0;String lenStr = headers.get("Content-Length");if (lenStr == null || lenStr.length() < 1)return len;try {len = Integer.parseInt(lenStr);} catch (NumberFormatException e) {e.printStackTrace();}return len;}public String getSessionId() {String sessionId = null;String val = headers.get("Set-Cookie");if (val != null && val.length() > 0) {String[] arrary = val.split(";");String sessStr = arrary[0];if (sessStr != null && sessStr.length() > 1) {arrary = sessStr.split("=");if (arrary.length > 1)sessionId = arrary[1];}}return sessionId;}/** * 是否是分块响应 * @return */public boolean isChunked() {String val = headers.get("Transfer-Encoding");if (val == null || val.length() < 1) return false;return "chunked".equals(val);}public String getRespLine() {return respLine;}public void setRespLine(String respLine) {this.respLine = respLine;}public Map<String, String> getHeaders() {return headers;}public void setHeaders(Map<String, String> headers) {this.headers = headers;}@Overridepublic String toString() {String str = this.respLine + "\r\n";Set<String> keys = this.headers.keySet();for (String key : keys) {str += (key + ":" + this.headers.get(key) + "\r\n");}return str;}}
RespMsg类：
package com.zws.http;/** * * @author wensh.zhu 2017-03-11 * */public class RespMsg {private String respCodeMsg;private String respBody;public String getRespCodeMsg() {return respCodeMsg;}public void setRespCodeMsg(String respCodeMsg) {this.respCodeMsg = respCodeMsg;}public String getRespBody() {return respBody;}public void setRespBody(String respBody) {this.respBody = respBody;}@Overridepublic String toString() {return respCodeMsg + "\n" + respBody;}}
测试类：
package com.zws.http;public class Example {public static void main(String[] args) {String uri = "http://localhost:8011/greeting";SimpleHttpGet get = new SimpleHttpGet(uri);RespMsg msg = get.req();String respCodeMsg = msg.getRespCodeMsg();String respBody = msg.getRespBody();System.out.println(respCodeMsg);System.out.println(respBody);}}
本文出自 “埃文” 博客，请务必保留此出处http://wenshengzhu.blog.51cto.com/5151285/1905510