io.jpom.util.HttpUtils Maven / Gradle / Ivy

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package io.jpom.util;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
import java.util.Set;

/**
 * 提供通过HTTP协议获取内容的方法
 * 所有提供方法中的params参数在内部不会进行自动的url encode，如果提交参数需要进行url encode，请调用方自行处理
 * 
 * https://blog.csdn.net/RobinsStruggle/article/details/86074058
 *
 * @author def
 */
public class HttpUtils {


    /**
     * 支持的Http method
     */
    private enum HttpMethod {
        POST, DELETE, GET, PUT, HEAD
    }


    private static String invokeUrl(String url, Map params, Map headers, int connectTimeout, int readTimeout, String encoding, HttpMethod method) {
        //构造请求参数字符串
        StringBuilder paramsStr = null;
        if (params != null) {
            paramsStr = new StringBuilder();
            Set> entries = params.entrySet();
            for (Map.Entry entry : entries) {
                String value = (entry.getValue() != null) ? (String.valueOf(entry.getValue())) : "";
                paramsStr.append(entry.getKey()).append("=").append(value).append("&");
            }
            //只有POST方法才能通过OutputStream(即form的形式)提交参数
            if (method != HttpMethod.POST) {
                url += "?" + paramsStr.toString();
            }
        }

        URL uUrl = null;
        HttpURLConnection conn = null;
        BufferedWriter out = null;
        BufferedReader in = null;
        try {
            //创建和初始化连接
            uUrl = new URL(url);
            conn = (HttpURLConnection) uUrl.openConnection();
            conn.setRequestProperty("content-type", "application/x-www-form-urlencoded");
            conn.setRequestMethod(method.toString());
            conn.setDoOutput(true);
            conn.setDoInput(true);
            //设置连接超时时间
            conn.setConnectTimeout(connectTimeout);
            //设置读取超时时间
            conn.setReadTimeout(readTimeout);
            //指定请求header参数
            if (headers != null && headers.size() > 0) {
                Set headerSet = headers.keySet();
                for (String key : headerSet) {
                    conn.setRequestProperty(key, headers.get(key));
                }
            }

            if (paramsStr != null && method == HttpMethod.POST) {
                //发送请求参数
                out = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream(), encoding));
                out.write(paramsStr.toString());
                out.flush();
            }

            //接收返回结果
            StringBuilder result = new StringBuilder();
            in = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding));
            String line = "";
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
            return result.toString();
        } catch (Exception e) {
            //处理错误流，提高http连接被重用的几率
            try {
                byte[] buf = new byte[100];
                InputStream es = conn.getErrorStream();
                if (es != null) {
                    while (es.read(buf) > 0) {
                        ;
                    }
                    es.close();
                }
            } catch (Exception e1) {
                e1.printStackTrace();
            }
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            //关闭连接
            if (conn != null) {
                conn.disconnect();
            }
        }
        return null;
    }


    /**
     * POST方法提交Http请求，语义为“增加”
     * 
     * 注意：Http方法中只有POST方法才能使用body来提交内容
     *
     * @param url            资源路径（如果url中已经包含参数，则params应该为null）
     * @param params         参数
     * @param headers        请求头参数
     * @param connectTimeout 连接超时时间（单位为ms）
     * @param readTimeout    读取超时时间（单位为ms）
     * @param charset        字符集（一般该为“utf-8”）
     * @return resopen
     */
    public static String post(String url, Map params, Map headers, int connectTimeout, int readTimeout, String charset) {
        return invokeUrl(url, params, headers, connectTimeout, readTimeout, charset, HttpMethod.POST);
    }
}