写文件
import java.io.Fileimport java.io.FileNotFoundException
import java.io.FileOutputStream
import java.io.IOException
import java.io.OutputStreamWriter
import java.io.UnsupportedEncodingException
import java.io.Writer
public class WriteFile {
public static void main(String[] args) {
File file = new File("F:" + File.separator + "abcd.txt")
try {
// 注意,这个地方,那个true的参数,代表如果这个文件已经存在了,就把新的内容添加到该文件的最后
// 如果你想重新创建新文件,把true改成false就好了
Writer writer = new OutputStreamWriter(new FileOutputStream(file, true), "GBK")
StringBuilder builder = new StringBuilder()
for (int i = 0 i < 100 i++) {
int temp = (int) ((Math.random() + 1) * 1000)
builder.append(String.valueOf(temp))
builder.append("|")
temp = (int) ((Math.random() + 1) * 1000)
builder.append(String.valueOf(temp)).append("\n")
}
writer.write(builder.toString())
writer.close()
} catch (UnsupportedEncodingException e) {
e.printStackTrace()
} catch (FileNotFoundException e) {
e.printStackTrace()
} catch (IOException e) {
e.printStackTrace()
}
}
}
读文件
import java.io.BufferedReaderimport java.io.File
import java.io.FileInputStream
import java.io.InputStreamReader
public class ReadFile {
public static void main(String[] args) {
File file = new File("F:" + File.separator + "abcd.txt")
String s = ""
try {
InputStreamReader read = new InputStreamReader(new FileInputStream(file), "GBK")
BufferedReader reader = new BufferedReader(read)
String line
while ((line = reader.readLine()) != null) {
s += line + "\n"
}
reader.close()
read.close()
} catch (Exception e) {
e.printStackTrace()
}
System.out.println(s)
}
}数据的格式:
import java.util.Scanner
public class Demo {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in)
System.out.println("请输入一个整数")
int x = scan.nextInt()
System.out.println("输入的证书是:"+x)
}