step1:新建一个演示类demo
step2:导入 包文件，在包名下，类名之上输入如下代码。
import java.util.Scanner;
step3:在类中的代码如下：
public static void main(String[] args) { //创建一个键盘录入对象input Scanner input = new Scanner(System.in); System.out.println("please input “学生姓名”"); String studentName = input.next().intern(); System.out.println("please input “科目名称”"); String subject = input.next().intern(); System.out.println("please input“科目成绩”"); double result = input.nextDouble(); //调用Student类的方法 Student stu = new Student(); stu.setStudentName(studentName); stu.setSubject(subject); stu.setResult(result); Student.getInformation(stu);}
step4:新建一个Student类，设置类的各个成员变量，创建一个学生个人信息的方法。如下：
public class Student { private String studentName; private String subject; private double result; private String eveluate; //创建一个信息输出方法 public static void getInformation(Student studentInformation) { System.out.println("学生个人信息"); //获取学生姓名返回的成员变量值 System.out.println("姓名：" + studentInformation.getStudentName()); //获取科目成员变量的返回值 System.out.println("科目：" + studentInformation.getSubject()); //获取成绩成员变量的返回值 System.out.println("成绩：" + studentInformation.getResult()); //获取等级成员变量的返回值 System.out.println("等级：" + studentInformation.getEveluate()); } //使用getXxx()和setXxx()对各个私有成员变量进行限定 //对学生姓名进行输入和输出的设置 public String getStudentName() { return this.studentName; } public void setStudentName(String studentName) { this.studentName = studentName; } //对成绩等级变量设置 public String getEveluate() { return this.eveluate; } public void setEveluate(String eveluate) { this.eveluate = eveluate; } //对科目成员变量进行设置 public String getSubject() { return this.subject; } public void setSubject(String subject) { this.subject = subject; } public double getResult() { return this.result; } //对成绩进行等级划分 public void setResult(double result) { if (result >= 95) { this.result = result; this.eveluate = "A+"; } else if (result < 90 && result >= 85) { this.result = result; this.eveluate = "A"; } else if (result >= 80 && result < 85) { this.result = result; this.eveluate = "B+"; } else if (result >= 75 && result < 80) { this.result = result; this.eveluate = "B"; } else if (result >= 70 && result < 75) { this.result = result; this.eveluate = "C+"; } else if (result >= 60 && result < 70) { this.result = result; this.eveluate = "C"; } else if (result >= 50 && result < 60) { this.result = result; this.eveluate = "D"; } else { this.result = result; this.eveluate = "E"; } }}
运行结果1：
please input “学生姓名”
李小明
please input “科目名称”
数学
please input“科目成绩”
98
学生个人信息
姓名：李小明
科目：数学
成绩：98.0
等级：A+
运行结果2：
please input “学生姓名”
王强
please input “科目名称”
英语
please input“科目成绩”
52
学生个人信息
姓名：王强
科目：英语
成绩：52.0
等级：D
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
public class SystemInTest
{
public static void main(String[] args)
{
try
{
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
FileWriter fw=new FileWriter("F:\\io\\abc.txt");
BufferedWriter bw=new BufferedWriter(fw);
System.out.println("输入你要输入到文件的内容，移over结束：");
String s;
while(true)
{
s=br.readLine();
if("over".equals(s))
break;
bw.write(s);
bw.newLine();
}
bw.close();
fw.close();
br.close();
isr.close();
}
catch (FileNotFoundException e)
{
System.out.println("操作的文件不存在");
}
catch(IOException e)
{
System.out.println("发生IO操作异常");
}
}
}
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
public class SystemInTest
{
public static void main(String[] args)
{
try
{
InputStreamReader isr=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(isr);
FileWriter fw=new FileWriter("F:\\io\\abc.txt");
BufferedWriter bw=new BufferedWriter(fw);
System.out.println("输入你要输入到文件的内容，移over结束：");
String s;
while(true)
{
s=br.readLine();
if("over".equals(s))
break;
bw.write(s);
bw.newLine();
}
}
catch (FileNotFoundException e)
{
System.out.println("操作的文件不存在");
}
catch(IOException e)
{
System.out.println("发生IO操作异常");
}
finally
{
try
{
bw.close();
fw.close();
br.close();
isr.close();
}
catch(Exception ex) {}
}
}
}
释放资源的语句最好写在finally中，这样即使程序运行过程中抛出异常，对应的资源也可以得到及时释放
import java.io.PrintStream;
import java.util.Scanner;
public class TestDemo {
public static void main(String[] args) throws FileNotFoundException {
PrintStream printStream = new PrintStream("Test.txt");
while (true) {
Scanner scanner = new Scanner(System.in);
System.out.println("输入文字,输入quit退出:");
String s = scanner.nextLine();
if ("quit".equals(s)) {
printStream.close();
break;
}
//保存到文件
printStream.println(s);
}
}
}
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
public class InputTest{
public static void main(String[] args) throws IOException{
BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter buf2 = new BufferedWriter(new FileWriter("e:/test.txt"));
System.out.println("请输入想要说的话:");
String str = buf.readLine();
while(!str.equals("YES")){
buf2.write(str);
buf2.newLine();
System.out.println("是否退出？输入YES退出:");
str = buf.readLine();
}
buf.close();
buf2.close();
}
}