自己收錄整理的JAVA 發起HTTP POST or GET請求工具類

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先上工具類代碼 使用方法在最下面

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import com.alibaba.fastjson.JSONObject;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.SocketTimeoutException;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;

public class HttpUtil {

    public enum  METHOD{
        POST("POST"),
        GET("GET"),
        JSON("application/json;charset=UTF-8"),
        URLENCODED("application/x-www-form-urlencoded"),
        FORM_DATA("multipart/form-data");

        private String value;

        public String getValue() {
            return value;
        }

        private METHOD(String value) {
            this.value = value;
        }
    }

    private HttpURLConnection connection;//網絡連接對象
    public static AtomicInteger timeoutNum = new AtomicInteger();//超時對象

    private METHOD type;//請求體數據類型
    private final String urlStr;//請求地址
    private final StringBuilder param;//請求參數
    private final Map<String, String> paramMap;//請求參數
    private final Map<String, String> headParam;//請求頭參數

    /**
     * 初始化HttpUtil
     * @param urlStr 請求地址
     */
    public HttpUtil(String urlStr) {
        this(urlStr,null);
    }

    /**
     * 初始化HttpUtil 傳入參數
     * 也可以後續使用setParam添加參數
     * @param urlStr 請求地址
     * @param paramMap 請求參數
     */
    public HttpUtil(String urlStr, Map<String, String> paramMap) {
        this.urlStr = urlStr;
        this.headParam = new HashMap<String, String>();

        if (null == paramMap) this.paramMap = new HashMap<String, String>();
        else this.paramMap = paramMap;

        this.param = new StringBuilder();
        for (String key : paramMap.keySet()) {
            param.append(key + "=" + paramMap.get(key) + "&");
        }
    }

    /**
     * 按照指定請求方式 初始化請求 
     * @param method 請求方法 GET OR POST
     */
    public void init(METHOD method) {
        try{
            URL url = null;
            switch (method){
                case GET:
                    url = new URL(urlStr + "?" + param.toString());
                    connection = (HttpURLConnection) url.openConnection();
                    break;
                case POST:
                    //打開連接
                    url = new URL(urlStr);
                    connection = (HttpURLConnection) url.openConnection();
                    connection = (HttpURLConnection) url.openConnection();
                    connection.setUseCaches(false);
                    connection.setDoInput(true);
                    connection.setDoOutput(true);
                    connection.setRequestMethod("POST");
                    connection.setInstanceFollowRedirects(true);
                    connection.setConnectTimeout(30000);
                    connection.setReadTimeout(30000);
                    break;
            }

            //設置請求頭
            for (String key : headParam.keySet()) {
                connection.setRequestProperty(key, headParam.get(key));
            }
            this.initParameter();
        }catch (Exception e){
            throw new RuntimeException("HttpURLConnection初始化異常");
        }
    }

    /**
     * 獲取請求結果  在init方法後執行
     * @return 請求結果
     */
    public String result(){
        this.checkConnection();
        try{
            connection.connect();
            InputStream input = null;
            if (connection.getResponseCode() == 200) {
                input = connection.getInputStream();
            } else {
                input = connection.getErrorStream();
            }
            return new String(readInputStream(input), "UTF-8");
        }catch (Exception e){
            throw new RuntimeException("獲取網絡請求結果時發生異常");
        }
    }

    /**
     * 初始化POST請求參數
     */
    private void initParameter() throws IOException {
        String body = "";
        //沒有請求體
        if (null == type) return;
        switch (type){
            case URLENCODED:
                body = param.toString();
                break;
            case JSON:
                //對象轉JSON  我用的是阿里爸爸的fastjson  你可以用別的
                body = JSONObject.toJSONString(paramMap);
                break;
            case FORM_DATA:
                throw new RuntimeException("該類型還未整理");
        }

//        System.out.println(body);//看看請求體長啥樣
        OutputStream out = null;
        try{
            out = connection.getOutputStream();
            out.write(body.getBytes("utf-8"));
            out.flush();
        }catch (UnknownHostException e){
            timeoutNum.incrementAndGet();
            throw new RuntimeException("設置網絡請求參數時發生異常");
        }catch (SocketTimeoutException e){
            timeoutNum.incrementAndGet();
            throw new RuntimeException("設置網絡請求參數時發生異常");
        }catch (IOException e){
            timeoutNum.incrementAndGet();
            throw new RuntimeException("設置網絡請求參數時發生異常");
        }finally {
            if(null != out){
                out.close();
            }
        }
    }

    /**
     * 設置請求頭
     * 必須在init方法前執行
     * @param head
     * @param value
     */
    public void setHttpHead(String head, String value){
        headParam.put(head, value);
    }

    /**
     * 設置參數
     * 必須在init方法前執行
     * @param key
     * @param value
     */
    public void setParam(String key, String value){
        paramMap.put(key, value);
        param.append(key + "=" + paramMap.get(key) + "&");
    }

     /**
     * 設置請求體格式
     * 必須在init方法前執行
     * @param head 請求體格式
     */
    public void setHttpHead(METHOD head){
        switch (head){
            case POST:
            case GET:
                break;
            default:
                this.type = head;
                headParam.put("Content-Type", head.getValue());
        }
    }

    /**
     * @param inStream
     * @return
     * @throws Exception
     */
    public static byte[] readInputStream(InputStream inStream) throws Exception {
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = inStream.read(buffer)) != -1) {
            outStream.write(buffer, 0, len);
        }
        byte[] data = outStream.toByteArray();
        outStream.close();
        inStream.close();
        return data;
    }

    /**
     * 檢查網絡連接對象是否初始化
     */
    public void checkConnection(){
        if (null == connection)
            throw new RuntimeException("HttpURLConnection未初始化");
    }
}

GET方法

//請求參數
Map paramMap = new HashMap();
paramMap.put("aaaa","參數一");
paramMap.put("bbbbb", "參數二");

//創建工具類對象
HttpUtil net = new HttpUtil("請求地址不需要'?'",paramMap);
//按照GET方法初始化
net.init(HttpUtil.METHOD.GET);
//拿到結果
net.result();

POST方法

//請求參數
Map paramMap = new HashMap();
paramMap.put("aaaa","參數一");
paramMap.put("bbbbb", "參數二");

//創建工具類對象 
HttpUtil net = new HttpUtil("請求地址不需要'?'",paramMap);
//也可以後續添加參數  需要在init()前
net.setParam("cccc", "參數三");

//設置請求體格式爲application/x-www-form-urlencoded或者application/json
//POST請求必填
net.setHttpHead(HttpUtil.METHOD.URLENCODED);
//可以init前使用setHttpHead設置請求頭  帶上token等參數
net.setHttpHead("token", "123465");
//按照POST方法初始化
net.init(HttpUtil.METHOD.POST);
//拿到結果
net.result();