http请求工具类

import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
import java.util.Set;

@Slf4j
public class HttpUtil {

    /**
     * 发送POST请求
     *
     * @param url    地址
     * @param params 消息体
     * @return
     */
    public static String doPost(String url, Map<String, Object> params) {
        return doPost(url, params, null);
    }

    /**
     * 发送POST请求
     *
     * @param url        地址
     * @param params     消息体
     * @param httpParams url参数
     * @return
     */
    public static String doPost(String url, Map<String, Object> params, Map<String, String> httpParams) {
        return doPost(url, params, httpParams, null);
    }

    public static String doPost(String url, Map<String, Object> params, Map<String, String> httpParams, Map<String, String> headParams) {
        try {
            url = setUrl(httpParams, url);
            log.info("=POST=========================\n正在请求：{}", url);
            URL urlObj = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection();
            conn.setRequestMethod("POST");
            conn.setConnectTimeout(5000);
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.addRequestProperty("Content-Type", "application/json");
            if (headParams != null) {
                for (Map.Entry<String, String> item : headParams.entrySet()) {
                    conn.addRequestProperty(item.getKey(), item.getValue());
                }
            }
            if (params != null) {
                OutputStream os = conn.getOutputStream();
                os.write(JSON.toJSONString(params).getBytes());
                os.flush();
            }

            conn.connect();
            int code = conn.getResponseCode();
            if (code == 200) {
                return receive(conn);
            }
            return "{\"errno\": \"" + code + "\", \"message\":\"" + receive(conn, true) + "\"}";
        } catch (Exception e) {
            e.printStackTrace();
            return "{\"errno\":-1,\"error\": \"" + e.getMessage() + "\"}";
        }
    }

    public static String doPut(String url, Map<String, Object> params, Map<String, String> httpParams) {
        return doPut(url, params, httpParams, null);
    }

    public static String doPut(String url, Map<String, Object> params, Map<String, String> httpParams, Map<String, String> headParams) {
        try {
            url = setUrl(httpParams, url);
            log.info("=PUT=========================\n正在请求：{}", url);
            URL urlObj = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection();
            conn.setRequestMethod("PUT");
            conn.setConnectTimeout(5000);
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.addRequestProperty("Content-Type", "application/json");
            if (headParams != null) {
                for (Map.Entry<String, String> item : headParams.entrySet()) {
                    conn.addRequestProperty(item.getKey(), item.getValue());
                }
            }
            if (params != null) {
                OutputStream os = conn.getOutputStream();
                os.write(JSON.toJSONString(params).getBytes());
                os.flush();
            }
            conn.connect();
            int code = conn.getResponseCode();
            if (code == 200) {
                return receive(conn);
            }
            return "{\"errno\": \"" + code + "\"}";
        } catch (Exception e) {
            e.printStackTrace();
            return "{\"errno\":-1,\"error\": \"" + e.getMessage() + "\"}";
        }
    }

    public static String doGet(String url, Map<String, String> params, Map<String, String> headParams) {
        try {
            url = setUrl(params, url);
            log.info("=GET=========================\n正在请求：{}", url);
            URL urlObj = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) urlObj.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(5000);
            conn.setDoInput(true);
            conn.setDoOutput(true);
            if (headParams != null) {
                for (Map.Entry<String, String> item : headParams.entrySet()) {
                    conn.addRequestProperty(item.getKey(), item.getValue());
                }
            }
            conn.connect();
            int code = conn.getResponseCode();
            if (code == 200) {
                return receive(conn);
            }
            return "{\"errno\": \"" + code + "\", \"message\":\"" + receive(conn, true) + "\"}";
        } catch (Exception e) {
            e.printStackTrace();
            return "{\"errno\": -1,\"error\": \"" + e.getMessage() + "\"}";
        }
    }

    /**
     * 通过http参数格式化url地址
     *
     * @param httpParams
     * @param url
     * @return
     */
    public static String setUrl(Map httpParams, String url) {
        if (httpParams != null) {
            if (!url.contains("?")) {
                url += "?";
            }
            if (!httpParams.isEmpty()) {
                url += joinHttpParam(httpParams, "&");
            }
        }
        return url;
    }

    public static String joinHttpParam(Map o, String flag) {
        StringBuffer strBuff = new StringBuffer();
        Set<Map.Entry> set = o.entrySet();
        for (Map.Entry item : set) {
            strBuff.append(item.getKey());
            strBuff.append("=");
            strBuff.append(item.getValue());
            strBuff.append(flag);
        }
        return strBuff.toString().substring(0, strBuff.length() - 1);
    }

    /**
     * 接收处理返回数据
     *
     * @param conn
     * @return
     * @throws Exception
     */
    private static String receive(HttpURLConnection conn) throws Exception {
        return receive(conn, false);
    }

    /**
     * 接收处理返回数据
     *
     * @param conn  连接信息
     * @param error 是否错误信息
     * @return
     * @throws Exception
     */
    public static String receive(HttpURLConnection conn, boolean error) throws Exception {
        if (error) {
            return "";
        }
        InputStream is = conn.getInputStream();
        String result = "";
        byte[] buffer = new byte[2048];
        byte[] total = new byte[0];
        int size = -1;
        while ((size = is.read(buffer)) != -1) {
            byte[] temp = new byte[size + total.length];
            System.arraycopy(total, 0, temp, 0, total.length);
            System.arraycopy(buffer, 0, temp, total.length, size);
            total = temp;
        }
        result = new String(total, "UTF-8");
        log.info("返回结果：{}\n===========================", result);
        return result;
    }
}