JavaEE——将访问的内容按照指定格式文件下载下来

 （1）如下代码是在Controller里面，当发送HttpServletRequest 请求之后，将服务器返回的HttpServletResponse响应内容下载下来

@ResponseBody
    @RequestMapping(value = "getDown.do",method = RequestMethod.GET)
    public String getDown(ModelMap map,@RequestParam int shipMmsi,@RequestParam int startTime,@RequestParam int endTime,HttpServletRequest request,
                          HttpServletResponse response) throws Exception {
//设置编码
        response.setCharacterEncoding("utf-8");

//setContentType为文件上传下载重要属性设置方法，详细可查看链接：http://blog.sina.com.cn/s/blog_a03d702f010143tw.html
//http://zhangjunhd.blog.51cto.com/113473/19631

        response.setContentType("multipart/form-data");

        String fileName = "ship_" + shipMmsi + "_start_" + startTime + "_end_" + endTime+".txt";
        response.setHeader("Content-Disposition", "attachment;fileName="
                + fileName);

        String fileContent = listOneShipHistory_chinese(shipMmsi, startTime, endTime);//

        String filePath="download";

        //写文件
        FileUtils file=new FileUtils(fileName,filePath);
        file.saveFile2(fileContent);

        //下载文件
        if(file.down(request,response)){
            System.out.println("success");
        }else{
            System.out.println("fail");
        }
        return null;
    }

（2）获取数据内容并格式化  

public String listOneShipHistory_chinese(int shipMmsi,int startTime,int endTime){
        List<ShipHistoryPosition> list= oneShipPosService.oneShipHistoryPositions(shipMmsi, startTime, endTime);//调用后端接口获取数据
        SimpleDateFormat dateFormat=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

//        换行符
        String n="\r\n";
        String f=",";
        String msiInfo="";

        if(list.size()==0){
            msiInfo="目标编号:"+shipMmsi+"在"+dateFormat.format((long)startTime*1000)+"至"+dateFormat.format((long)endTime*1000)+"时间范围内无数据";
            return msiInfo;
        }

//将筛选的数据格式化并返回
        msiInfo+="目标编号:"+shipMmsi+n;
        msiInfo+="时间范围:"+dateFormat.format((long)startTime*1000)+"至"+dateFormat.format((long)endTime*1000)+n;
        msiInfo+="位置信息:"+n;

        for(ShipHistoryPosition position:list){
            msiInfo+="经度:"+position.getLongitude()/600000+f;
            msiInfo+="纬度:"+position.getLatitude()/600000+f;
            msiInfo+="船艏向:"+position.getHeading()+f;

            Long time= (long) position.getTime()*1000;
            msiInfo+="时间:"+dateFormat.format(time)+n;
        }

        return msiInfo;
    }

（3）文件读写操作工具类，包含上面调用的两个方法
 

package com.ict.common;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.ArrayList;
import java.util.List;

public class FileUtils {
    public String fileRoad;
    public String fileName;
    public String filePath;

    public FileUtils(String fileName, String filePath){
        this.fileName=fileName;
        this.filePath=filePath;
        this.fileRoad=getFileRoad()+filePath;
    }

    public FileUtils(){};

//    逐行读取文件加入list
    public List<String> getFileContent(String filePath) throws Exception{
        List<String> list=new ArrayList<>();

        FileReader fr = new FileReader(filePath);
        BufferedReader bufferedreader = new BufferedReader(fr);
        String instring;
        while ((instring = bufferedreader.readLine())!= null) {
            list.add(instring);
        }
        fr.close();

        return list;
    }

    public void saveFile(String content){
        String  fileRoad=this.fileRoad+"/"+this.fileName;
        System.out.println(fileRoad);

       FileWriter writer;
       try {
           writer = new FileWriter(fileRoad,true);//有true参数则追加写
           writer.write(content);
           writer.write("\r\n");

           writer.flush();
           writer.close();
       } catch (IOException e) {
           e.printStackTrace();
       }
    }

    public void saveFile2(String content){
        String  fileRoad=this.fileRoad+"/"+this.fileName;
        System.out.println(fileRoad);

        FileWriter writer;
        try {
            writer = new FileWriter(fileRoad);//无true参数则覆盖写
            writer.write(content);
            writer.write("\r\n");

            writer.flush();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //获取项目所在路径
    public String getFileRoad(){
        String path1 = Thread.currentThread()
                .getContextClassLoader().getResource("").getPath();
        return path1;
    }

    public boolean down( HttpServletRequest request,
                        HttpServletResponse response){
        try {
            String path1 = getFileRoad()
                    + filePath + "/" + fileName;
            System.out.println(path1);
            InputStream inputStream = new FileInputStream(path1);

            OutputStream os = response.getOutputStream();
            byte[] b = new byte[2048];
            int length;
            while ((length = inputStream.read(b)) > 0) {
                os.write(b, 0, length);
            }
            // 这里主要关闭。
            os.close();
            inputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return false;
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }
        return true;
    }
}