System.setIn
时间: 2024-05-14 21:15:05 浏览: 7
(System.in) is a method in Java that allows you to redirect the standard input stream to a different source. This can be useful when testing or debugging code that relies on user input, as it allows you to simulate input without actually typing it in manually. The method takes a parameter of type InputStream, which is the new source for the input stream. For example, to redirect standard input to a file, you would use the following code:
```
FileInputStream input = new FileInputStream("input.txt");
System.setIn(input);
```
After this code is executed, any calls to `System.in` will read from the file `input.txt` instead of from the keyboard.
相关问题
system.setproperty
System.setProperty() is a method in Java that allows you to set a system property. A system property is a key-value pair that is stored in the system's properties table.
Syntax:
```java
public static String setProperty(String key, String value)
```
Parameters:
- key: a string representing the name of the system property.
- value: a string representing the value of the system property.
Example:
```java
System.setProperty("my.property", "Hello, World!");
```
In this example, we are setting a system property with the key "my.property" and the value "Hello, World!". This system property can then be accessed using the getProperty() method:
```java
String myProperty = System.getProperty("my.property");
System.out.println(myProperty); // Output: "Hello, World!"
```
public class void main Add(){ if (num > stu.length - 1) { System.out.println("系统成员已满"); return; } Student student = new Student();//创建一个对象,用于接收信息,最后传给数组对象 System.out.println("请输入学号"); String number= in.next(); for (int i = 0; i\u003C num; i++) { while (stu[i].getNumber().equals(number)) { System.out.println("学号输入重复,请重新输入"); number= in.next(); } } student.setNumber(number); System.out.println("请输入姓名"); student.setName(in.next()); System.out.println("请输入性别"); student.setSex(in.next()); System.out.println("请输入班级"); student.setClass1(in.next()); stu[num] = student; num++; System.out.println("添加成功"); } } 改错
您需要将该方法的声明修改为 `public static void main(String[] args)`。同时,需要在方法前后加上一对大括号 `{}`,表示该方法的开始和结束。修改后的代码如下:
```
public static void main(String[] args) {
if (num > stu.length - 1) {
System.out.println("系统成员已满");
return;
}
Student student = new Student();//创建一个对象,用于接收信息,最后传给数组对象
System.out.println("请输入学号");
String number = in.next();
for (int i = 0; i < num; i++) {
while (stu[i].getNumber().equals(number)) {
System.out.println("学号输入重复,请重新输入");
number = in.next();
}
}
student.setNumber(number);
System.out.println("请输入姓名");
student.setName(in.next());
System.out.println("请输入性别");
student.setSex(in.next());
System.out.println("请输入班级");
student.setClass1(in.next());
stu[num] = student;
num++;
System.out.println("添加成功");
}
```