http常见的get请求方式和set请求方式。

一、Get请求方式

　　以下是我写的一个用get请求方式获取api工厂中汇率的类。

package com.example;

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

import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

public class Testexchange {
    private static String source = "USD";
    private static String goal = "CNY";
    private static String money = "1200";
    private static String apiKey = "e9be757798f64552415b2de06b29f435";
    static String result = "";
    static BufferedReader in = null;

    public static void main(String[] args) throws IOException {

        getRate();

    }

    public static void getRateByOk() throws IOException{
        OkHttpClient client = new OkHttpClient();

        Request request = new Request.Builder()
                .url("http://a.apix.cn/apixmoney/exchangerate/exchange?source=" + source + "&goal=" + goal + "&money="
                        + money)
                .get().addHeader("accept", "application/json").addHeader("content-type", "application/json")
                .addHeader("apix-key", apiKey).build();

        Response response = null;
        try {
            response = client.newCall(request).execute();
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println(response.body().string());
    }

    public static void getRate() throws IOException {
        String mUrl = "http://a.apix.cn/apixmoney/exchangerate/exchange?source=" + source + "&goal=" + goal + "&money="
                + money;
        try {
            URL url = new URL(mUrl);
            URLConnection conn = url.openConnection();
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            conn.setRequestProperty("accept", "application/json");
            conn.setRequestProperty("content-type", "application/json");
            conn.setRequestProperty("apix-key", apiKey);
            // 建立实际的连接
            conn.connect();
            // 获取所有响应头字段
            Map<String, List<String>> map = conn.getHeaderFields();
            // 遍历所有的响应头字段
            for (String key : map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            // 定义 BufferedReader输入流来读取URL的响    应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                    System.out.println(result);
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }

    }
}

二、Post方式发起请求

  /**
     * 向指定 URL 发送POST方法的请求
     *
     * @param url
     *            发送请求的 URL
     * @param param
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return 所代表远程资源的响应结果
     */
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new PrintWriter(conn.getOutputStream());
            // 发送请求参数
            out.print(param);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！"+e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }
}