java - 从数组列表中返回字符串值

Question

我正在尝试改革/重建列表中的字符串值。我正在从文本文件中读取值。文本文件中的值如下格式。

    H|013450107776|10/15/2019
    D|TXN001|10/15/2019|013450107806|LCUATADA05|1000.00|PAYMENT FOR SERVICE|Successful
    D|TXN002|10/15/2019|013458001581|LCUATADA04|1500.00|INVOICE 001|Successful
    D|TXN003|10/15/2019|013450107784|LCUATADA01|1750.00|SEPT PAYMENT|Successful
    H|007442500211|11/05/2019
    D|1000000489|007442500211|0009204332|85585.44|SEPT PAYMENT|Successful
    H|007442500213|11/05/2019
    D|1000000489|007442500211|0009204332|85585.44|SEPT PAYMENT|Successful
    D|1000000490|007442500211|0009204332|85585.44|SEPT PAYMENT|Successful
    D|1000000491|007442500211|0009204332|85585.44|SEPT PAYMENT|Successful

找到以下用于读取文件的代码。

 public Integer  readFile(String fileName,String path){  
        List<String> lineList = new ArrayList<>();
        try {
            reader = new BufferedReader(new FileReader(
                    path+"/"+fileName));
            String line = reader.readLine();
            count =0;
            while (line != null) {
                lineList.add(line);
                count ++;
                line = reader.readLine();
            }
            reader.close();
        } catch (IOException e) {
        }
        String packet=searchHeader(lineList);
        try{
            unmarshallResponsePacket(packet); 
        }catch(Exception e){
        }
        return count;
    }

lineList 包含类似

的值

[ H|013450107776|10/15/2019,D|TXN001|10/15/2019|013450107806|LCUATADA05|1000.00|PAYMENT FOR SERVICE|Successful,D|TXN002|10/15/2019|013450107806|LCUATADA05|1000.00|PAYMENT FOR SERVICE|Successful,D|TXN002|10/15/2019|013458001581|LCUATADA04|1500.00|INVOICE 001|Successful, D|TXN003|10/15/2019|013450107784|LCUATADA01|1750.00|SEPT PAYMENT|Successful,H|007442500211|11/05/2019,D|1000000489|007442500211|0009204332|85585.44|SEPTPAYMENT|Successful...] 


  How i can form the string value(header information followed by detail 
  information) like
 "H|013450207776|10/15/2019
  D|0000TXN001|10/15/2019|013450107806|LCUATADA05|1000.00|PAYMENT FOR 
  SERVICE|Successful" from the List

Answer 1

using below code i resolved the issue.

private static String packetList(List<String> oldPacketList) {
        StringBuffer sb3 = new StringBuffer();

        String header="" ;  

        for(int i = 0; i < oldPacketList.size(); i++) {
            if(oldPacketList.get(i).startsWith("H")) {
                headertest=oldPacketList.get(i);
                continue;
            }
            else {
                sb3.append(header.trim().toString()+(System.getProperty("line.separator")));
                sb3.append(oldPacketList.get(i).trim().toString()+(System.getProperty("line.separator")));


            }
        }

        System.out.println("----------------output--------------------");

        return sb3.toString().trim();
    }