java下载链接图片到本地远程

获取文件所在路径

//                	String path = System.getProperty("user.dir")     	
                	String path ="./picturePath/"+pictureName +".bmp";       

tomcat服务器

1.server.xml文件增加

<Context docBase="E:\tomcat\downlogo" path="/downlogo" />	

2.web.xml文件改为true

    <servlet>
        <servlet-name>default</servlet-name>
        <servlet-class>org.apache.catalina.servlets.DefaultServlet</servlet-class>
        <init-param>
            <param-name>debug</param-name>
            <param-value>0</param-value>
        </init-param>
        <init-param>
            <param-name>listings</param-name>
            <param-value>true</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;


public class DownLogo {

    public static boolean downloadPicture(String pictureSourceServer,String fileName,StringBuffer res) {
        try {
            fileName = fileName+".bmp";
            //tomcat服务器端口和文件地址映射
//            String pictureSourceServer = "http://192.168.1.1:8080/downlogo/";
            String saveDir = "./picture/";
            File saveFile = new File(saveDir, fileName);
            File dir = new File(saveDir);
            //判断文件夹是否存在
            if (!dir.exists()) {
                dir.mkdirs();
            }
			//判断文件夹内的文件是否存在
            if (saveFile.exists()) {
                return true;
            } else {
            	//下载
                URL url = new URL(pictureSourceServer+fileName);
                HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
                int responseCode = httpConn.getResponseCode();
                if (responseCode == HttpURLConnection.HTTP_OK) {
                    InputStream inputStream = httpConn.getInputStream();
                    OutputStream outputStream = new FileOutputStream(saveFile);
                    //开辟一块缓冲区间
                    byte[] buffer = new byte[4096];
                    int bytesRead;
                    while ((bytesRead = inputStream.read(buffer)) != -1) {
                        outputStream.write(buffer, 0, bytesRead);
                    }
                    //关闭输入输出流
                    inputStream.close();
                    outputStream.close();
                    return true;
                }else {
                    res.append("服务器没有找到picture源文件"+fileName);                    
                    return false;
                }
            }
        }catch (Exception e){
            e.printStackTrace();
            // 将异常堆栈信息保存为字符串
            StringWriter sw = new StringWriter();
            PrintWriter pw = new PrintWriter(sw);
            e.printStackTrace(pw);
            // 获取完整的堆栈信息
            String stackTrace = sw.toString();
			UI.TAData.append("下载picture源文件异常："+stackTrace+"\n");
            res.append("下载picture源文件异常："+stackTrace);
            return false;
        }
    }

    public static void main(String[] args) {
//        String fileName = "xxx"; // 指定文件名
//        String[] strings = new String[]{"xx1","xx2","xx3","xx4"};
        String[] strings = new String[]{"xxx1"};
        StringBuffer res = new StringBuffer();
        for (String string : strings) {
            boolean downFlag = downloadPicture(pictureSourceServer,string,res);
            System.out.println(downFlag);
            if (res.length()>0)
            System.out.println(res);
        }
    }

}