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List<String> lines=new ArrayList<String>();  BufferedReader br = new BufferedReader(new FileReader(fileName));String line = null;while ((line = br.readLine()) != null) {       lines.add(line);}br.close();

  

Java的I/O类处理如图:

Reader 类是 Java 的 I/O 中读字符的父类,而 InputStream 类是读字节的父类,InputStreamReader 类就是关联字节到字符的桥梁,它负责在 I/O 过程中处理读取字节到字符的转换,而具体字节到字符的解码实现它由 StreamDecoder 去实现,在 StreamDecoder 解码过程中必须由用户指定 Charset 编码格式。值得注意的是如果你没有指定 Charset,将使用本地环境中的默认字符集,例如在中文环境中将使用 GBK 编码。

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总结:Java读取数据流的时候,一定要指定数据流的编码方式,否则将使用本地环境中的默认字符集。

public static List<Organ> fileinput() {// TODO Auto-generated method stubList<Organ> list = new ArrayList<Organ>();try {String fileName = "C://Users/Administrator/Desktop/备份/bustno.txt";StringBuffer sb = new StringBuffer("");InputStreamReader sr = new InputStreamReader(new FileInputStream(fileName),"UTF-8");BufferedReader br = new BufferedReader(sr);String str = null;while ((str = br.readLine()) != null) { String[] firstSplit = str.split("\n");int recordNum = firstSplit.length;for(int i=0; i < recordNum;i++){String[] one = str.split("\\|");Organ organ = new Organ();organ.setParentID(0);organ.setOrganValue(one[0].substring(0, 3));organ.setOrganName(one[1]);list.add(organ);}}br.close();sr.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.print("read succeeded");return list;}

 list结果集分组:

private static void fenzu(String filepath) throws IOException, ParseException {// TODO Auto-generated method stubSimpleDateFormat simpleDate = new SimpleDateFormat("yyyy-MM");List<String[][]> valueList = new ArrayList<String[][]>();//将结果集转化为二维数组  StringBuffer sb = new StringBuffer("");          InputStreamReader sr = new InputStreamReader(new FileInputStream(filepath),"UTF-8");          BufferedReader br = new BufferedReader(sr);          String str = null;          List<Canal> list = new ArrayList<Canal>();          while ((str = br.readLine()) != null) {               String[] firstSplit = str.split("\n");              int recordNum = firstSplit.length;              for(int i=0; i < recordNum;i++){                  String[] one = str.split("\t");                  Canal canalone = new Canal();                  canalone.setCanal(one[0]);                  canalone.setSa_tx_m(one[1]);                  canalone.setCr_tx_amt(one[2]);                  list.add(canalone);              }}                    System.out.print("list size :"+list.size()+ "\n");      //结果集分组    List uniqueList = new ArrayList();//存放Canal个数    for (int j = 0; j < list.size(); j++) {    Canal canal = list.get(j);    if (!uniqueList.contains(canal.getCanal()))     {    System.out.print("uniqueList not contains : " +canal.getCanal().toString() + "\n" );    String[][] b = new String[2][12];//String[0][]为canal,长度为1,String[1][]对应每个月的数值    b[0][0] = canal.getCanal();//canal    String amtValue = list.get(j).getCr_tx_amt();// 金额    Calendar Date = Calendar.getInstance();    Date.setTime(simpleDate.parse(canal.getSa_tx_m()));    int month = Date.get(Calendar.MONTH); // 因为数组的编号要减一,这里不用加一    b[1][month] = amtValue;    uniqueList.add(canal.getCanal());//将canal种类放在集合里    valueList.add(b);//将数值集合放在valueList里    } else {    for (int k = 0; k < valueList.size(); k++) {    String[][] b = valueList.get(k);    if (b[0][0].equals(canal.getCanal())) {    valueList.remove(k);//先remove结果集里不完整的记录    System.out.print("has found canal : " + canal.getCanal() + "\n");    String amtValue = canal.getCr_tx_amt();// 金额    Calendar Date = Calendar.getInstance();    Date.setTime(simpleDate.parse(canal    .getSa_tx_m()));    int month = Date.get(Calendar.MONTH); // 因为数组的编号要减一,这里不用加一    b[1][month] = amtValue.toString();    valueList.add(b);//加了数值再add到分组的list里    break; //找到就返回    }    }    }    }      }

  

 

文章转载于:https://www.cnblogs.com/kxdblog/p/4069883.html

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