Http請求：java.net.URLConnection java.net.HttpURLConnection



URLConnection

package com.conan.javase.http_https;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

/**
 * Created by Conan on 2016/11/25.
 */
public class HttpRequest {
    public static String sendGet(String url, String param) {
        StringBuffer sb = new StringBuffer();
        BufferedReader bin = null;
        try {
            String urlNameString = url + "?" + param;
            URL realURL = new URL(urlNameString);
            URLConnection conn = realURL.openConnection();
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.connect();

            //遍歷返回的頭
            Map<String, List<String>> map = conn.getHeaderFields();
            for (Map.Entry entry : map.entrySet())
                System.out.println(entry.getKey() + " : " + entry.getValue());

            bin = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = bin.readLine()) != null)
                sb.append(line);
        } catch (IOException e) {
            System.out.println("發送GET請求出現異常");
            // 能處理就處理，不要打印太長的裹腳布錯誤信息
            e.printStackTrace();
        } finally {
            try {
                if (bin != null)
                    bin.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }

    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader bin = null;
        StringBuffer sb = new StringBuffer();
        try {
            URL realURL = new URL(url);
            URLConnection conn = realURL.openConnection();
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            //發送POST請求必須要這兩行
            conn.setDoInput(true);
            conn.setDoOutput(true);
            //不使用緩存
            conn.setUseCaches(false);
            out = new PrintWriter(conn.getOutputStream());
            out.print(param);
            out.flush();
            bin = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = bin.readLine()) != null)
                sb.append(line);
        } catch (IOException e) {
            System.out.println("發送POST請求出現異常");
            e.printStackTrace();
        } finally {
            try {
                if (out != null)
                    out.close();
                if (bin != null)
                    bin.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        String s = HttpRequest.sendGet("http://localhost:8080/Catalog/my/get", "name=liu&pass=123");
        System.out.println("GET : " + s);
        String g = HttpRequest.sendPost("http://localhost:8080/Catalog/my/post", "liufeiqiang");
        System.out.println("POST : " + g);
    }
}

HttpURLConnection

package com.conan.javase.http_https;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * Created by Conan on 2016/11/25.
 */
public class HttpUrlRequest {
    public static String sendGet(String url, String param) {
        HttpURLConnection conn = null;
        StringBuffer sb = new StringBuffer();
        BufferedReader bin = null;
        try {
            url = url + "?" + param;
            URL realUrl = new URL(url);
            // HttpURLConnection 專門用來進行處理HTTP請求的
            conn = (HttpURLConnection) realUrl.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Content-type", "application/x-java-serialized-object");
            // 防止網絡異常情況下超時
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(30000);
            conn.connect();
            bin = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = bin.readLine()) != null)
                sb.append(line);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bin != null)
                    bin.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }

    public static String sendPost(String url, String param) {
        HttpURLConnection conn = null;
        StringBuffer sb = new StringBuffer();
        BufferedReader bin = null;
        PrintWriter pw=null;
        try {
            url = url + "?" + param;
            URL realUrl = new URL(url);
            // HttpURLConnection 專門用來進行處理HTTP請求的
            conn = (HttpURLConnection) realUrl.openConnection();
            conn.setRequestMethod("POST");
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 防止網絡異常情況下超時
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(30000);
            conn.connect();
            // 發送請求參數
            pw=new PrintWriter(conn.getOutputStream());
            pw.write(param);
            pw.flush();
            bin = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = bin.readLine()) != null)
                sb.append(line);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bin != null)
                    bin.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        String s = HttpUrlRequest.sendGet("http://localhost:8080/Catalog/my/get", "name=liu&pass=123");
        System.out.println("GET : " + s);
    }
}