问题描述
我编写了一个Java程序来提取文件的各行，并挑选出一个特定的ID，然后将其从HEX转换为ASCII字符。直到找到“ 0D”十六进制字符（似乎是回车符）（不知道该怎么做）后，它对两个文件的工作效果很好。
遇到这种情况时，它将结束行输出（不应该这样做）。我不知道发生了什么。
文件1包含的字符直到ID = xxx：LENGHT = 8，之后才需要转换8个十六进制字符。之后，程序将转换并在同一行中添加文本。我需要它们在同一行上以找出模式。
import java.io.*;
import java.util.Scanner;
import java.io.FileWriter;
import java.io.IOException;
public class FrameDecoder {
public static void main(String[] args) throws IOException {
try {
// Sortam frameurile cu id-ul tinta
File fisierSursa = new File("file1.txt"); //Fisierul original
FileWriter fisierData = new FileWriter("file2.txt"); //Fisierul cu frameurile care au id-ul cautat
FileWriter fisierTranzit = new FileWriter("file3.txt"); //Fisier cu caractere HEX,care va fi sters.
Scanner citireSursa = new Scanner(fisierSursa);
while (citireSursa.hasNextLine()){
String data = citireSursa.nextLine();
//System.out.println("data = " + data);
int intIndex = data.indexOf("ID=289"); // idul pe care il cauti
int intIndex2 = data.indexOf("ID=1313"); //al doilea id pe care il cauti
if (intIndex != -1 || intIndex2 != -1){
char[] text = data.tochararray();
int counter = 0;
for (int i=0; i<text.length; i++){
if (text[i] == ':' && counter < 5){
counter++;
}
if (text[i] == ':' && counter == 5){
fisierTranzit.write(text[i+1]);
fisierTranzit.write(text[i+2]);
}
}
fisierTranzit.write("\r\n");
fisierData.write(data + "\r\n");
}
}
citireSursa.close();
fisierTranzit.close();
fisierData.close();
// Convertire HEX to ASCII
FileWriter fisierAscii = new FileWriter("file4.txt"); //Fisier care va contine caraterele ASCII decodate
File fisierTranzitRedeschis = new File("file3.txt"); //Reinitializam fisierul tranzit pentru a putea citi din el
Scanner citireTranzit = new Scanner(fisierTranzitRedeschis);
while (citireTranzit.hasNextLine()){
String data2 = citireTranzit.nextLine();
System.out.println("data2 = " + data2);
if (data2.length() % 2 != 0){
System.err.println("Invalid hex string!");
return;
}
StringBuilder builder = new StringBuilder();
for (int i=0; i<data2.length(); i=i+2){
//Impartim sirul in grupe de cate doua caractere
String s = data2.substring(i,i+2);
//Convertim fiecare grup in integer folosinf valueOfTheMetod
int n = Integer.valueOf(s,16);
//Convertim valoare integer in char
builder.append((char)n);
}
fisierAscii.write(builder.toString() + "\r\n");
//System.out.println(builder.toString());
}
citireTranzit.close();
fisierAscii.close();
//Stergem fisierul 3
File stergereFisier3 = new File("file3.txt");
if(stergereFisier3.delete()){
System.out.println("File 3 deleted successfully");
}else{
System.out.println("Failed to delete file 3");
}
// Combinam fisierele
PrintWriter fisierFinal = new PrintWriter("file5.txt");
BufferedReader br1 = new BufferedReader(new FileReader("file2.txt"));
BufferedReader br2 = new BufferedReader(new FileReader("file4.txt"));
String line1 = br1.readLine();
String line2 = br2.readLine();
//loop to copy lines
//of file1.txt and file2.txt
//to file3.txt alternatively
while (line1 != null || line2 !=null){
if(line1 != null){
fisierFinal.print(line1 + " ");
line1 = br1.readLine();
}
if (line2 != null){
fisierFinal.println(line2 );
line2 = br2.readLine();
}
}
fisierFinal.flush();
//closing resources
br1.close();
br2.close();
fisierFinal.close();
System.out.println("Merged files succesfully");
//Stergem fisierul 2 si 4
File stergereFisier2 = new File("file2.txt");
File stergereFisier4 = new File("file4.txt");
if(stergereFisier2.delete() && stergereFisier4.delete()){
System.out.println("Files 2 and 4 deleted successfully");
}else{
System.out.println("Failed to delete files 2 and 4");
}
}catch (FileNotFoundException e){
System.out.println("An error occurred.");
e.printstacktrace();
}catch (IOException e){
System.out.println("No data to print");
e.printstacktrace();
}
}
}
编辑：打印十六进制字符时，我作了一点欺骗，并提出了条件，如果遇到0D，只需将其替换为00。就可以了。我也会尝试您的方法，那似乎比我的还好。
for (int i=0; i<text.length; i++){
if (text[i] == ':' && counter < 5){
counter++;
}
if (text[i] == ':' && counter == 5){
if(text[i+1] == '0' && text[i+2] == 'D'){
fisierTranzit.write('0');
fisierTranzit.write('0');
}
else{
fisierTranzit.write(text[i+1]);
fisierTranzit.write(text[i+2]);
}
}
}
解决方法
回车符\r（十六进制0D）是标准行分隔符之一，并且Scanner.hasNextLine()和nextLine()方法假定它必须终止当前行。
要获得更多控制，请将扫描仪的delimiter设置为仅换行符\n，并使用hasNext / next方法代替hasNextLine / nextLine方法。例如：
Scanner citireTranzit = new Scanner(fisierTranzitRedeschis);
citireTranzit.useDelimiter("\n");
while (citireTranzit.hasNext()){
String data2 = citireTranzit.next();
...
}