Java导入导出csv文件，以及导出出现科学计数法的问题解决

//导出 

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 = "";
        if(row != null){
          Object o = ((Map)row).get( propertyEntry.getKey());
           str=(o == null ? "" :o.toString());
        }
        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;  
} 

// getBom（），防止导出乱码

public static String getBOM() {

     byte b[] = {(byte)0xEF, (byte)0xBB, (byte)0xBF};
     return new String(b);
}

导出会出现科学计数法的问题解决：在后面加个 “\ t” 的

row.put("1","哈哈1"+"\t");
row.put("2", "哈哈2");
row.put("3","哈哈3");

 

//导入

 /**
     * 导入
     * 
     * @param file csv文件(路径+文件)
     * @return
     */
    public static List importCsv(File file){
        List dataList=new ArrayList();
        
        BufferedReader br=null;
        try { 
            br = new BufferedReader(new FileReader(file));
            String line = ""; 
            while ((line = br.readLine()) != null) { 
                dataList.add(line);
            }
        }catch (Exception e) {
        }finally{
            if(br!=null){
                try {
                    br.close();
                    br=null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
 
        return dataList;
    }

参考：https://www.cnblogs.com/linjiqin/p/3535067.html