HTTP開發學習記錄

1.測試服務器端口是否可達

public boolean isHostConnectable(String host,int port）{
	Socke socket = new Socket();
	try{
		socket.connect(new InetSocketAddress(host,port),timeOut);//在指定超時時間內嘗試連接
	}catch(IOException e){
		return false;
	}finally{
	try{
		socket.close();
	}catch(IOException e){
	}
	}
	return true;
}

附:不靠譜的 isReachable

try{
	InetAddress ad = InetAddress.getByName(host);
	return ad.isReachable(1000);//isReachable不靠譜：測試1000毫秒內false，socket.connect耗時只13毫秒
}catch(UnknownHostException e){
}catch(IOException e){
}

2.從多個服務器中選擇連接較優的（設計思路：連接耗時越短越優）

//返回單個服務器端口連接時長
public long preHandler(String url,int port){
	long curNanoTime = System.nanoTime() - ;
	long curMilTime = System.currentTimeMillis();
	isHostConnectable(url,port);
	long intervalN = System.nanoTime() - curNanoTime;//納秒
	long intervalM = System.currentTimeMillis() - curMilTime;//毫秒
	return intervalM;
}
//選擇較優
public String[] choose(){
	String[] hosts = hostString.split(",");//hostString爲自定義的多個服務器ip字符串
	long[] intervals = new long[hosts.length];
	int i = 0;
	for(String host : hosts){
		intervals[i] = preHandler(host,port);//計算每個服務端口的連接時長
		i++;
	}
	//冒泡排序，起始最優
	for(int j = 1; j < intervals.length; j++){
		for(int k = 0; k < intervals.length - j; k++){
			if(intervals[k] > intervals[k + 1]){
				String temp = hosts[k];
				hosts[k] = hosts[k + 1];
				hosts[k + 1] = temp;
			}
		}
	}
	return hosts;
}

3.執行http請求

Strng url = "http://192.168.1.10:8080/aaa";
String charset = "utf-8";
String JSONString = JSON.toJSONString(objectBean);//objectBean爲對象bean
HttpPost httpPost = new HttpPost(url);
CloseableHttpClient client = HttpClients.createDefault();

StringEntity entity = new StrngEntity(JSONString,charset);//亂碼
entity.setContentEncoding(charset);
entity.setContentType("applicaiton/json");
httpPost.setEntity(entity);
HttpResponse resp = null;
try{
	resp = client.execute(httpPost);
}catch(exception e){
}
if(resp !=null && resp.getStatusLine().getStatusCode() == 200){
	//成功
}