Java程序输入与输出方式
1 输入方式
1.1 Scanner类输入
import java.util.Scanner;
/**
* @author wcs
* @date 2021/7/29 20:09
*/
public class InputTest01 {
public static void main(String[] args) {
//Scanner类输入
Scanner s = new Scanner(System.in);
System.out.println("请输入用户名:");
String name = s.nextLine();
System.out.println("请输入密码:");
int pwd = s.nextInt();
System.out.println("欢迎您" + name + ",您的密码是" + pwd);
}
}
1.2 控制台输入
import java.io.Console;
/**
* @author wcs
* @date 2021/7/29 20:51
*/
public class InputTest02 {
public static void main(String[] args) {
//控制台输入
Console c = System.console();
System.out.print("请输入账号:");
String a = c.readLine();
System.out.print("请输入密码:");
String p = new String(c.readPassword());
System.out.printf("您的账号是:%s,密码:%s。 \n", a, p);
}
}
1.3 对话框输入
import javax.swing.*;
import java.io.Console;
import java.util.Scanner;
import javax.swing.*;
/**
* @author wcs
* @date 2021/7/29 20:51
*/
public class InputTest03 {
public static void main(String[] args) {
//对话框输入
String user = JOptionPane.showInputDialog("请输入用户名:");
String Pwd = JOptionPane.showInputDialog("请输入密码:");
System.out.println(user + Pwd);
}
}
2 输出方式
2.1 print和对话框输出
import javax.swing.*;
/**
* @author wcs
* @date 2021/7/29 20:09
*/
public class OutputTest01 {
public static void main(String[] args) {
System.out.println("Hello World!");
System.err.printf("我是错误信息!");
JOptionPane.showMessageDialog(null, "Hello World!", "系统提示", JOptionPane.QUESTION_MESSAGE);
}
}
运行结果:
![](https://img.laitimes.com/img/9ZDMuAjOiMmIsIjOiQnIsIyZuBnL4ElMkZ2Z3I0QxkXVHF2bvwVOy8CX3AzLcFjMwIzLcRXZu5Sas9Gbuk2Lc9CX6MHc0RHaiojIsJye.png)
2.2 输出内容到文件中
import java.io.FileWriter;
import java.io.IOException;
/**
* @author wcs
* @date 2021/7/29 20:38
*/
public class OutputTest02 {
public static void main(String[] args) throws IOException {
String str1 = "Hello ";
String str2 = "World";
FileWriter fw = new FileWriter("user.txt");
fw.write(str1);
fw.write(str2);
fw.close();
}
}
运行结果:
2.3 控制台格式化输出
import java.util.Date;
/**
* @author wcs
* @date 2021/7/29 20:46
*/
public class OutputTest03 {
public static void main(String[] args) {
System.out.printf("%d %02d %.2f %2$06d \n", 2, 5, 1.98245);
System.out.println(System.currentTimeMillis());
System.out.println(new Date().getTime());
System.out.printf("%n%tF %1$tT%n", System.currentTimeMillis());
}
}