您将必须逐行读取文件，然后将新列插入每一行。这是使用BufferedReader和BufferedWriter的解决方案
public void addColumn(String path,String fileName) throws IOException{ BufferedReader br=null; BufferedWriter bw=null; final String lineSep=System.getProperty("line.separator"); try { File file = new File(path, fileName); File file2 = new File(path, fileName+".1");//so the //names don't conflict or just use different folders br = new BufferedReader(new InputStreamReader(new FileInputStream(file))) ; bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file2))); String line = null; int i=0; for ( line = br.readLine(); line != null; line = br.readLine(),i++) { String addedColumn = String.valueOf(data.get(i)); bw.write(line+addedColumn+lineSep); } }catch(Exception e){ System.out.println(e); }finally { if(br!=null) br.close(); if(bw!=null) bw.close(); }}
