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java通过java.net.URL发送http请求调用接口

一般在*.html,*.jsp页面中我们通过使用ajax调用接口,这个是我们通常用的。对于这些接口,大都是本公司写的接口供自己调用,所以直接用ajax就可以。但是,如果是多家公司共同开发一个东西,一个功能可能要调多个接口,一两个ajax可以在jsp页面上显示,但是如果多了,就不能写这么多ajax在前端了。这时候需要封装一成一个接口,在接口里面如何调用其他接口呢?这就用到了java.net.URL这个类。

java.net.URL用法如下

     BufferedReader in=null;
        java.net.HttpURLConnection conn=null;
        String msg = "";// 保存调用http服务后的响应信息
        try
        {
       //实例化url java.net.URL url
= new java.net.URL(path);
       //根据url获取HttpURLConnection conn
= (java.net.HttpURLConnection) url.openConnection();
       //设置请求的参数 conn.setRequestMethod(
"POST"); conn.setConnectTimeout(5 * 1000);// 设置连接超时时间为5秒 conn.setReadTimeout(20 * 1000);// 设置读取超时时间为20秒 conn.setDoOutput(true); // 使用 URL 连接进行输出,则将 DoOutput标志设置为 true conn.setDoInput(true); conn.setRequestProperty("Content-Type", "text/xml;charset=UTF-8"); //conn.setRequestProperty("Content-Encoding","gzip"); conn.setRequestProperty("Content-Length", String.valueOf(params.length())); //设置请求内容(长度)长度 OutputStream outStream = conn.getOutputStream(); // 返回写入到此连接的输出流 outStream.write(params.getBytes()); //将参数写入流中 outStream.close();//关闭流 if (conn.getResponseCode() == 200) { // HTTP服务端返回的编码是UTF-8,故必须设置为UTF-8,保持编码统一,否则会出现中文乱码 in = new BufferedReader(new InputStreamReader((InputStream) conn.getInputStream(), "UTF-8")); msg = in.readLine(); } }catch(Exception ex) { ex.printStackTrace(); }finally { if(null!=in) { in.close(); } if(null!=conn) { conn.disconnect(); } } return msg;

HttpUtil工具类 

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import java.net.HttpURLConnection;
import java.net.URL;


/**
 * http工具
 * @author lenovo
 *
 */
public final class HttpUtil {
    /**
     * 模拟http协议发送get请求
     **/
    public static String sendGetRequest(String url) {
        String result = "";
        InputStream in = null;

        HttpURLConnection connection = null;

        try {
            URL httpUrl = new URL(url);
            connection = (HttpURLConnection) httpUrl.openConnection();
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("Charset", "UTF-8");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            connection.setRequestMethod("GET");
            connection.connect();

            if (connection.getResponseCode() == 200) {
                in = connection.getInputStream();

                ByteArrayOutputStream bs = new ByteArrayOutputStream();
                int n = 0;
                byte[] datas = new byte[2048];

                while ((n = in.read(datas)) != -1) {
                    bs.write(datas, 0, n);
                }

                bs.flush();
                result = new String(bs.toByteArray(), "utf-8");
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }

            try {
                connection.disconnect();
            } catch (Exception ex) {
            }
        }

        return result;
    }

    /**
    * 模拟http协议发送post请求
    **/
    public static String sendPostRequest(String url, String param) {
        InputStream in = null;
        String result = "";
        HttpURLConnection connection = null;

        try {
            URL httpUrl = new URL(url);
            connection = (HttpURLConnection) httpUrl.openConnection();
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("Charset", "UTF-8");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            connection.setRequestMethod("POST");
            connection.setDoOutput(true);
            connection.setDoInput(true);
            connection.setUseCaches(false);
            connection.getOutputStream().write(param.getBytes("utf-8"));
            connection.getOutputStream().flush();

            if (connection.getResponseCode() == 200) {
                in = connection.getInputStream();

                ByteArrayOutputStream bs = new ByteArrayOutputStream();
                int n = 0;
                byte[] datas = new byte[2048];

                while ((n = in.read(datas)) != -1) {
                    bs.write(datas, 0, n);
                }

                bs.flush();
                result = new String(bs.toByteArray(), "utf-8");
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }

            try {
                connection.disconnect();
            } catch (Exception ex) {
            }
        }

        return result;
    }

    /**
     * 普通post文件上传
     */
    public static String upLoadAttachment(String url, String fileName, File file) {
        String result = null;

        HttpURLConnection connection = null;
        BufferedReader reader = null;

        try {
            URL httpUrl = new URL(url);
            connection = (HttpURLConnection) httpUrl.openConnection();
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("Charset", "UTF-8");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            connection.setRequestMethod("POST");
            connection.setConnectTimeout(5000);
            connection.setReadTimeout(5000);
            connection.setDoOutput(true);
            connection.setDoInput(true);
            connection.setUseCaches(false);

            String bound = "----------" + System.currentTimeMillis();
            connection.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + bound);

            StringBuilder sb = new StringBuilder();
            sb.append("--");
            sb.append(bound);
            sb.append("\r\n");
            sb.append("Content-Disposition: form-data;name=\"" + fileName +
                "\";filename=\"" + file.getName() + "\"\r\n");
            sb.append("Content-Type:application/octet-stream\r\n\r\n");

            byte[] data = sb.toString().getBytes("utf-8");
            OutputStream out = new DataOutputStream(connection.getOutputStream());
            out.write(data);

            DataInputStream in = new DataInputStream(new FileInputStream(file));
            int bytes = 0;
            byte[] bufferOut = new byte[1024];

            while ((bytes = in.read(bufferOut)) != -1) {
                out.write(bufferOut, 0, bytes);
            }

            in.close();

            byte[] foot = ("\r\n--" + bound + "--\r\n").getBytes("utf-8"); // 定义最后数据分隔线
            out.write(foot);
            out.flush();
            out.close();

            InputStream inn = connection.getInputStream();
            ByteArrayOutputStream bs = new ByteArrayOutputStream();
            int n = 0;
            byte[] datas = new byte[2048];

            while ((n = inn.read(datas)) != -1) {
                bs.write(datas, 0, n);
            }

            bs.flush();
            result = new String(bs.toByteArray(), "utf-8");

            return result;
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                connection.disconnect();
            } catch (Exception ex) {
            }
        }

        return null;
    }
}

 

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