简而言之，我只是试图获得一个小型的工作骨架程序，我可以用它来学习Http通信和＆＃34;感觉＆＃34;我的方式来弄清楚我最终需要一个更大的计划，我正在努力。这里的特定代码实际上只是Apache库中一个示例的切碎版本。我可以编译Apache网站上列出的示例，但是它们没有正常运行，给出了＆＃34; java.net.ConnectException＆＃34;。我认为它与Windows c-blocking这样的程序有关，不能建立连接，我需要以管理员身份运行它。然后我尝试将代码放入可执行的jar文件中，但是我得到了一个Can not-find-or-load-main-class错误。我是一个白痴还是Apache库有点过时/不适合Win 8 /其他什么？
以下代码：
package NewProject;
import java.net.Socket;
import org.apache.http.ConnectionReuseStrategy;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.impl.DefaultBHttpClientConnection;
import org.apache.http.impl.DefaultConnectionReuseStrategy;
import org.apache.http.message.BasicHttpRequest;
import org.apache.http.protocol.HttpCoreContext;
import org.apache.http.protocol.HttpProcessor;
import org.apache.http.protocol.HttpProcessorBuilder;
import org.apache.http.protocol.HttpRequestExecutor;
import org.apache.http.protocol.RequestConnControl;
import org.apache.http.protocol.RequestContent;
import org.apache.http.protocol.RequestExpectContinue;
import org.apache.http.protocol.RequestTargetHost;
import org.apache.http.protocol.RequestUserAgent;
import org.apache.http.util.EntityUtils;
class NewProject
{
public static void main(String[] args) throws Exception
{
HttpProcessor httpproc = HttpProcessorBuilder.create()
.add(new RequestContent())
.add(new RequestTargetHost())
.add(new RequestConnControl())
.add(new RequestUserAgent("Test/1.1"))
.add(new RequestExpectContinue(true)).build();
HttpRequestExecutor httpexecutor = new HttpRequestExecutor();
HttpCoreContext coreContext = HttpCoreContext.create();
HttpHost host = new HttpHost("localhost", 8080);
coreContext.setTargetHost(host);
Out os = new Out("TestOut.txt");
DefaultBHttpClientConnection conn = new DefaultBHttpClientConnection(8 * 1024);
ConnectionReuseStrategy connStrategy = DefaultConnectionReuseStrategy.INSTANCE;
try
{
String[] targets =
{
"http://www.google.com/"
};
for (int i = 0; i < targets.length; i++)
{
if (!conn.isOpen())
{
Socket socket = new Socket(host.getHostName(), host.getPort());
conn.bind(socket);
}
BasicHttpRequest request = new BasicHttpRequest("GET", targets[i]);
os.println(">> Request URI: " + request.getRequestLine().getUri());
httpexecutor.preProcess(request, httpproc, coreContext);
HttpResponse response = httpexecutor.execute(request, conn, coreContext);
httpexecutor.postProcess(response, httpproc, coreContext);
os.println("<< Response: " + response.getStatusLine());
os.println(EntityUtils.toString(response.getEntity()));
os.println("==============");
if (!connStrategy.keepAlive(response, coreContext))
{
conn.close();
}
else
{
os.println("Connection kept alive...");
}
}
}
catch (IndexOutOfBoundsException iob)
{
os.println("What happened here?");
}
finally
{
conn.close();
}
return;
}
}
答案 0 :(得分：1)
......他们没有正常运行，给出了“java.net.ConnectException”
这可能是由许多事情引起的。异常消息中有线索......您选择不与我们分享。
...“无法找到或加载Main-Class”
同样有多种可能的原因，并且异常消息中有线索......您选择不与我们分享。
但是你在你提供的错误消息片段中创建了一个JAR文件加上“Main-Class”提示的事实表明你在创建JAR文件时犯了一个错误;即你使用了错误的名称作为“Main-Class”属性。
鉴于源代码，“Main-Class”属性应为“NewProject.NewProject”。我怀疑你把它设置为其他东西。
第二种可能性是您没有正确处理对Apache库的依赖性。 Apache类需要位于JAR文件指定的类路径上。 （使用-cp启动时，您无法使用$CLASSPATH参数或java -jar。）
我是一个白痴还是Apache库有点过时/不适合Win 8 /其他？
Apache库没有任何问题。
答案 1 :(得分：0)
您发布的代码似乎有点低级别（例如直接与Socket连接进行交互）。下面发布的代码应该可以为您提供您正在寻找的内容。使用的类也为您提供了很多设置和获取http参数（例如标题，超时等）的进展。
package org.yaorma.example.http.client;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
public class HttpClientExample {
public static void main(String[] args) throws Exception {
String response;
response = get("http://www.google.com");
System.out.println("RESPONSE FROM GET -----------------------------------------");
System.out.println(response);
response = post("http://httpbin.org/post", "This is the message I posted to httpbin.org/post");
System.out.println("RESPONSE FROM POST -----------------------------------------");
System.out.println(response);
}
/**
* Method to post a request to a given URL.
*/
public static String post(String urlString, String message) {
try {
// get a connection
URL url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
// set the parameters
conn.setRequestMethod("POST");
conn.setDoOutput(true);
// send the message
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(message);
writer.flush();
writer.close();
os.close();
// get the response
conn.connect();
InputStream content = (InputStream) conn.getInputStream();
// read the response
BufferedReader in = new BufferedReader(new InputStreamReader(content));
String rtn = "";
String line;
while ((line = in.readLine()) != null) {
rtn += line + "\n";
}
return rtn;
} catch (Exception exp) {
throw new RuntimeException(exp);
}
}
/**
* Method to do a get from a given URL.
*/
public static String get(String urlString) {
try {
// get a connection
URL url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
// set the parameters
conn.setRequestMethod("GET");
conn.setDoOutput(true);
// get the response
conn.connect();
InputStream content = (InputStream) conn.getInputStream();
// read the response
BufferedReader in = new BufferedReader(new InputStreamReader(content));
String rtn = "";
String line;
while ((line = in.readLine()) != null) {
rtn += line + "\n";
}
return rtn;
} catch (Exception exp) {
throw new RuntimeException(exp);
}
}
}