java导出csv格式文件详解编程语言

import java.io.BufferedWriter;   
import java.io.File;   
import java.io.FileInputStream;   
import java.io.FileNotFoundException;   
import java.io.FileOutputStream;   
import java.io.IOException;   
import java.io.InputStream;   
import java.io.OutputStream;   
import java.io.OutputStreamWriter;   
import java.net.URLEncoder;   
import java.util.ArrayList;   
import java.util.Iterator;   
import java.util.LinkedHashMap;   
import java.util.List;   
import java.util.Map;   
 
import javax.servlet.http.HttpServletResponse;   
 
import com.alibaba.druid.util.StringUtils; 
    
 
    
/**  
 * 文件操作  
 */   
public class CSVUtils {   
     
     
    /** 
    * 功能说明：获取UTF-8编码文本文件开头的BOM签名。 
    * BOM(Byte Order Mark)，是UTF编码方案里用于标识编码的标准标记。例：接收者收到以EF BB BF开头的字节流，就知道是UTF-8编码。 
    * @return UTF-8编码文本文件开头的BOM签名 
    */ 
    public static String getBOM() { 
 
         byte b[] = {(byte)0xEF, (byte)0xBB, (byte)0xBF}; 
         return new String(b); 
    } 
     
  /**  
   * 生成CVS文件 
   * @param exportData  
   *       源数据List  
   * @param map  
   *       csv文件的列表头map  
   * @param outPutPath  
   *       文件路径  
   * @param fileName  
   *       文件名称  
   * @return  
   */   
  @SuppressWarnings("rawtypes")   
  public static File createCSVFile(List exportData, LinkedHashMap map, String outPutPath,   
                   String fileName) {   
    File csvFile = null;   
    BufferedWriter csvFileOutputStream = null;   
    try {   
      File file = new File(outPutPath);   
      if (!file.exists()) {   
        file.mkdirs();   
      }   
      //定义文件名格式并创建   
      csvFile =new File(outPutPath+fileName+".csv"); 
      file.createNewFile();   
      // UTF-8使正确读取分隔符","   
      //如果生产文件乱码，windows下用gbk，linux用UTF-8 
      csvFileOutputStream = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(   
        csvFile), "UTF-8"), 1024);   
       
      //写入前段字节流，防止乱码 
      csvFileOutputStream.write(getBOM()); 
      // 写入文件头部 
      for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator.hasNext();) {   
        java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator.next();   
        csvFileOutputStream.write((String) propertyEntry.getValue() != null ? (String) propertyEntry.getValue() : "" );   
        if (propertyIterator.hasNext()) {   
          csvFileOutputStream.write(",");   
        }   
      }   
      csvFileOutputStream.newLine();   
      // 写入文件内容   
      for (Iterator iterator = exportData.iterator(); iterator.hasNext();) {   
          Object row = (Object) iterator.next(); 
        for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator   
          .hasNext();) {   
          java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator   
            .next();   
          String str=row!=null?((String)((Map)row).get( propertyEntry.getKey())):"";
 
          if(StringUtils.isEmpty(str)){ 
              str=""; 
          }else{ 
              str=str.replaceAll("/"","/"/""); 
              if(str.indexOf(",")>=0){ 
                  str="/""+str+"/""; 
              } 
          } 
          csvFileOutputStream.write(str);   
          if (propertyIterator.hasNext()) {   
            csvFileOutputStream.write(",");   
          }   
        }   
        if (iterator.hasNext()) {   
          csvFileOutputStream.newLine();   
        }   
      }   
      csvFileOutputStream.flush();   
    } catch (Exception e) {   
      e.printStackTrace();   
    } finally {   
      try {   
        csvFileOutputStream.close();   
      } catch (IOException e) {   
        e.printStackTrace();   
      }   
    }   
    return csvFile;   
  }   
    
  /** 
   *     生成并下载csv文件 
   * @param response 
   * @param exportData 
   * @param map 
   * @param outPutPath 
   * @param fileName 
   * @throws IOException 
   */ 
  @SuppressWarnings("rawtypes") 
  public static void exportDataFile(HttpServletResponse response,List exportData, LinkedHashMap map, String outPutPath,String fileName) throws IOException{ 
      File csvFile = null;   
        BufferedWriter csvFileOutputStream = null;   
        try {   
          File file = new File(outPutPath);   
          if (!file.exists()) {   
            file.mkdirs();   
          }   
          //定义文件名格式并创建   
          csvFile =new File(outPutPath+fileName+".csv"); 
          if(csvFile.exists()){ 
             csvFile.delete();  
          } 
          csvFile.createNewFile();   
          // UTF-8使正确读取分隔符","   
          //如果生产文件乱码，windows下用gbk，linux用UTF-8 
          csvFileOutputStream = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(csvFile), "UTF-8"), 1024);   
          //写入前段字节流，防止乱码 
          csvFileOutputStream.write(getBOM()); 
          // 写入文件头部   
          for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator.hasNext();) {   
            java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator.next();   
            csvFileOutputStream.write((String) propertyEntry.getValue() != null ? (String) propertyEntry.getValue() : "" );   
            if (propertyIterator.hasNext()) {   
              csvFileOutputStream.write(",");   
            }   
          }   
          csvFileOutputStream.newLine();   
          // 写入文件内容   
          for (Iterator iterator = exportData.iterator(); iterator.hasNext();) {   
            Object row = (Object) iterator.next();   
            for (Iterator propertyIterator = map.entrySet().iterator(); propertyIterator   
              .hasNext();) {   
              java.util.Map.Entry propertyEntry = (java.util.Map.Entry) propertyIterator   
                .next();   
              String str=row!=null?((String)((Map)row).get( propertyEntry.getKey())):""; 
              if(StringUtils.isEmpty(str)){ 
                  str=""; 
              }else{ 
                  str=str.replaceAll("/"","/"/""); 
                  if(str.indexOf(",")>=0){ 
                      str="/""+str+"/""; 
                  } 
              } 
              csvFileOutputStream.write(str);   
              if (propertyIterator.hasNext()) {   
                csvFileOutputStream.write(",");   
              }   
            }   
            if (iterator.hasNext()) {   
              csvFileOutputStream.newLine();   
            }   
          }   
          csvFileOutputStream.flush();   
        } catch (Exception e) {   
          e.printStackTrace();   
        } finally {   
          try {   
            csvFileOutputStream.close();   
          } catch (IOException e) {   
            e.printStackTrace();   
          }   
        }   
         
         
        
        
        InputStream in = null;   
        try {   
          in = new FileInputStream(outPutPath+fileName+".csv");   
          int len = 0;   
          byte[] buffer = new byte[1024];   
          
          OutputStream out = response.getOutputStream();  
          response.reset();  
            
          response.setContentType("application/csv;charset=UTF-8");   
          response.setHeader("Content-Disposition","attachment; filename=" + URLEncoder.encode(fileName+".csv", "UTF-8"));   
          response.setCharacterEncoding("UTF-8");  
          while ((len = in.read(buffer)) > 0) {   
            out.write(new byte[] { (byte) 0xEF, (byte) 0xBB, (byte) 0xBF });   
            out.write(buffer, 0, len);   
          } 
          out.close(); 
        } catch (FileNotFoundException e) {   
        } finally {   
          if (in != null) {   
            try {   
              in.close();   
            } catch (Exception e) {   
              throw new RuntimeException(e);   
            }   
          }   
        } 
        
  } 
   
  /**  
   * 删除该目录filePath下的所有文件  
   * @param filePath  
   *      文件目录路径  
   */   
  public static void deleteFiles(String filePath) {   
    File file = new File(filePath);   
    if (file.exists()) {   
      File[] files = file.listFiles();   
      for (int i = 0; i < files.length; i++) {   
        if (files[i].isFile()) {   
          files[i].delete();   
        }   
      }   
    }   
  }   
    
  /**  
   * 删除单个文件  
   * @param filePath  
   *     文件目录路径  
   * @param fileName  
   *     文件名称  
   */   
  public static void deleteFile(String filePath, String fileName) {   
    File file = new File(filePath);   
    if (file.exists()) {   
      File[] files = file.listFiles();   
      for (int i = 0; i < files.length; i++) {   
        if (files[i].isFile()) {   
          if (files[i].getName().equals(fileName)) {   
            files[i].delete();   
            return;   
          }   
        }   
      }   
    }   
  }   
    
  /**  
   * 测试数据  
   * @param args  
   */   
  @SuppressWarnings({ "rawtypes", "unchecked" })   
  public static void main(String[] args) {   
    List exportData = new ArrayList<Map>();   
    Map row1 = new LinkedHashMap<String, String>();   
    row1.put("1", "11");   
    row1.put("2", "12");   
    row1.put("3", "13");   
    row1.put("4", "14");   
    exportData.add(row1);   
    row1 = new LinkedHashMap<String, String>();   
    row1.put("1", "21");   
    row1.put("2", "22");   
    row1.put("3", "23");   
    row1.put("4", "24");   
    exportData.add(row1);   
    LinkedHashMap map = new LinkedHashMap();   
 
    //设置列名 
    map.put("1", "第一列名称");   
    map.put("2", "第二列名称");   
    map.put("3", "第三列名称");   
    map.put("4", "第四列名称");   
    //这个文件上传到路径，可以配置在数据库从数据库读取，这样方便一些！ 
    String path = "E:/";   
 
   //文件名=生产的文件名称+时间戳 
    String fileName = "文件导出";   
    File file = CSVUtils.createCSVFile(exportData, map, path, fileName);   
    String fileName2 = file.getName();   
    System.out.println("文件名称：" + fileName2);   
  }   
}