每周JAVA学习汇总

本周我自学了Java的输入与输出
包括了：

1. 使用Scanner类进行输入
   导入Scanner类：import java.util.Scanner;
   创建Scanner对象：Scanner scanner = new Scanner(System.in);
   读取不同类型的数据：
   读取字符串：String inputString = scanner.nextLine();
   读取整数：int inputInt = scanner.nextInt();
   读取浮点数：double inputDouble = scanner.nextDouble();
   示例代码：
   java
   import java.util.Scanner;
   public class Main {
   public static void main(String[] args) {
   Scanner scanner = new Scanner(System.in);
   System.out.println("请输入一个字符串：");
   String inputString = scanner.nextLine();
   System.out.println("您输入的字符串是：" + inputString);
   System.out.println("请输入一个整数：");
   int inputInt = scanner.nextInt();
   System.out.println("您输入的整数是：" + inputInt);
   scanner.close();
   }
   }

2. 使用BufferedReader类进行输入
   导入BufferedReader类：import java.io.BufferedReader;
   导入InputStreamReader类：import java.io.InputStreamReader;
   创建BufferedReader对象：BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
   读取字符串：String inputString = reader.readLine();
   示例代码：
   java
   import java.io.BufferedReader;
   import java.io.InputStreamReader;
   public class Main {
   public static void main(String[] args) throws Exception {
   BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
   System.out.println("请输入一个字符串：");
   String inputString = reader.readLine();
   System.out.println("您输入的字符串是：" + inputString);
   reader.close();
   }
   }

3. 使用System.out.println()和System.out.print()方法
   输出字符串：System.out.println("Hello, world!");
   输出变量值：int num = 10; System.out.println("数值为：" + num);
   4.使用PrintWriter类进行输出
   导入PrintWriter类：import java.io.PrintWriter;
   创建PrintWriter对象：PrintWriter writer = new PrintWriter(System.out);
   输出内容：writer.println("Hello, world!");
   刷新并关闭输出流：writer.flush(); writer.close();
   示例代码：
   java
   import java.io.PrintWriter;
   public class Main {
   public static void main(String[] args) {
   PrintWriter writer = new PrintWriter(System.out);
   writer.println("Hello, world!");
   writer.flush();
   writer.close();
   }
   }
   并完成了我的java语言的第一个程序“输出Hello world”
   public class HelloWorld {
   public static void main(String[] args) {
   System.out.println("Hello, world!");
   }
   }