java代码使用Get请求或者Post请求获取网络内容_java 发送 get获取网络资源

引入的依赖包，也可以去 阿里仓库下载   ————>前往阿里云仓库

<dependency>
  <groupId>org.apache.commons</groupId>
  <artifactId>commons-lang3</artifactId>
  <version>3.7</version>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>5.2.1.RELEASE</version>
</dependency>

一个Get Post请求的java代码

 
import org.apache.commons.lang3.StringUtils;
import org.springframework.util.StreamUtils;
 
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.Map;
 
public class HttpUtil {
 
    /**
     * post请求
     * @param urlStr
     * @param param
     * @param userAgent
     * @return
     */
    public static String httpPost(String urlStr,String param,String userAgent){
        try {
            URL url = new URL(urlStr);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded");
            conn.setReadTimeout(5000);
            conn.setConnectTimeout(60 * 1000);
            if(StringUtils.isNotBlank(userAgent)){
                conn.setRequestProperty("User-Agent",
                        userAgent);
            }
            conn.setUseCaches(false);
            conn.setDoInput(true);
            conn.setDoOutput(true);
            BufferedOutputStream out = new BufferedOutputStream(conn
                    .getOutputStream());
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream(),"utf-8"));
            bw.write(param);
            bw.flush();
            bw.close();
 
            if (conn.getResponseCode()==200){
                BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(),"utf-8"));
                String tempStr = null;
                String str = "";
                while ((tempStr=br.readLine())!=null){
                    str +=tempStr;
                }
                br.close();
                return str;
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
    /**
     * post请求
     * @param urlStr
     * @param xmlParam
     * @return
     */
    public static String httpPost(String urlStr,String xmlParam){
        return httpPost(urlStr,xmlParam,null);
    }
 
 
    /**
     * 调用外部接口，并返回响应结果
     * @param httpUrl
     * @param params
     * @return
     * @throws Exception
     */
    public static String sendHttpPostRequest(String httpUrl, Map<String, String> params) throws Exception{
 
        URL url = new URL(httpUrl);
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();
        conn.setRequestMethod("POST");
        conn.setDoOutput(true);
 
        if(params != null && params.size() > 0){
            StringBuilder sb = new StringBuilder();
            for(Map.Entry<String, String> entry : params.entrySet()){
                sb.append("&").append(entry.getKey()).append("=").append(entry.getValue());
            }
            conn.getOutputStream().write(sb.substring(1).getBytes("utf-8"));
        }
        conn.connect();
        String responseContent = StreamUtils.copyToString(conn.getInputStream(), Charset.forName("utf-8"));
 
        conn.disconnect();
        return responseContent;
    }
 
    public static String sendHttpGetRequest(String httpUrl, Map<String, String> params) throws Exception{
 
        try {
            if(params != null && params.size() > 0){
                StringBuilder sb = new StringBuilder();
                for(Map.Entry<String, String> entry : params.entrySet()){
                    sb.append("&").append(entry.getKey()).append("=").append(entry.getValue());
                }
                sb = new StringBuilder(sb.substring(1));
                if(httpUrl.contains("?")){
                    httpUrl += "&"+sb.toString();
                }else{
                    httpUrl += "?"+sb.toString();
                }
            }
            URL url = new URL(httpUrl);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setRequestMethod("GET");
            conn.setDoOutput(true);
            conn.connect();
            String responseContent = StreamUtils.copyToString(conn.getInputStream(), Charset.forName("utf-8"));
            conn.disconnect();
            return responseContent;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }
 
 
    //获得网络路径
    public static InputStream getImageStream(String url) throws Exception{
        HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
        connection.setReadTimeout(5000);
        connection.setConnectTimeout(5000);
        connection.setRequestMethod("GET");
        connection.addRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36");
        if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
            return connection.getInputStream();
        }else{
            throw new Exception("响应状态：" + connection.getResponseCode() + "\n" +
                    "响应内容：" + connection.getResponseMessage());
        }
    }
 
    //判断当前请求是否有效
    public static boolean sendGetRequestAck(String url) throws Exception{
        HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
        connection.setReadTimeout(5000);
        connection.setConnectTimeout(5000);
        connection.setRequestMethod("GET");
        connection.addRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36");
        if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
            return true;
        }else{
            return false;
        }
    }
 
    //把字节流转换成字节数组
    public static byte[] toByteArray(InputStream input) {
        try {
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024*4];
            int n = 0;
            while (-1 != (n = input.read(buffer))) {
                output.write(buffer, 0, n);
            }
            return output.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }
 
    //把字节数组转换成字节流
    public static InputStream toInputStream(byte[] bytes){
        return new ByteArrayInputStream(bytes);
    }
 
    //字节流转换字节流
    public static InputStream toInputStream(InputStream input){
        return toInputStream(toByteArray(input));
    }
}