我的任务是编写两个 java 程序。一个程序创建一个名为“userinput.txt”的文件，然后将用户输入的所有内容写入该文件。完成后，将创建一个名为“Checksum.txt”的新文件，该文件将在读取其中的内容后记下“userinput.txt”文件的校验和。
第二个程序只是读取相同的“userinput.txt”文件，然后生成一个校验和并将其打印到控制台上（我还必须让程序读取另一个 checksum.txt 文件并将其显示在控制台中以比较两者但我还没有解决这个问题）。
我为这两个编写了程序，但我的问题是它们都是不同的校验和，即使它们正在读取同一个文件。我使用 Adler32，但 CRC32 也给了我两个不同的校验和（控制台上的校验和总是与 checksum.txt 中存储的校验和不同），坦率地说，我不确定是什么原因造成的：/
这是接受用户输入并生成校验和文件的代码：
package attemp2;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
import java.util.zip.Adler32;
import java.util.zip.CheckedInputStream;
public class main {
public static void main(String[] args) throws IOException {
System.out.println("All inputs will be recorded into a sigle file. Enter 'x' when done. A checksum File will aslo be created at the end");
FileWriter fw = new FileWriter("d:/input.txt", false); // clears previous entry in file.
while (true) {
Scanner input = new Scanner(System.in); //get user input
String ch = input.nextLine(); //stores user input
System.out.println(ch); //prints out what user just inputed
if (ch.equals("x")) { //stops running if 'x' is entered
break;
}
BufferedWriter writer = new BufferedWriter(new FileWriter("d:/input.txt", true));
writer.write(ch);
writer.newLine(); // Add new line
writer.close();
}
try {
FileReader reader = new FileReader("d:/input.txt");
BufferedReader br = new BufferedReader(reader);
// read line by line String line;
String read = "";
String line;
while ((line = br.readLine()) != null) {
read = read + line;
//prints out text in file currently
System.out.println(line);
}
//checksum.txt generation
byte buffer[] = read.getBytes();
ByteArrayInputStream bais = new ByteArrayInputStream(buffer);
CheckedInputStream cis = new CheckedInputStream(bais, new Adler32());
byte readBuffer[] = new byte[buffer.length];
cis.read(readBuffer);
FileOutputStream out = new FileOutputStream("d://checksum.txt");
BufferedWriter wrt = new BufferedWriter(new FileWriter("d:/checksum.txt", false));
wrt.write(Long.toString(cis.getChecksum().getValue()));
wrt.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
读取文件并在控制台中生成校验和的代码：
package check;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Scanner;
import java.util.zip.Adler32;
public class CheckSum {
private Adler32 checksum;
private String filepath;
InputStream inputStream;
public CheckSum(String filepath) throws FileNotFoundException{
this.filepath = filepath;
checksum = new Adler32();
inputStream = new FileInputStream(filepath);
}
public long generateChecksum() throws IOException{
int c;
while((c = inputStream.read())!=-1){
checksum.update(c);
}
return checksum.getValue();
}
public void read() throws IOException{
File file = new File(filepath);
BufferedReader br = new BufferedReader(new FileReader(file));
String st;
while ((st = br.readLine()) != null) {
System.out.println(st);
}
}
public static void main(String[] args) throws Exception{
Scanner scanner = new Scanner(System.in);
String filepath = "d:/input.txt";
CheckSum checksum = new CheckSum(filepath);
checksum.read();
System.out.println("For the file: "+filepath);
System.out.println("The checksum generated is: "+checksum.generateChecksum());
}
}