public class StudentDemo { public static void main(String[] args) { Scanner in = new Scanner(System.in); // 判断类型并循环输入 String stuNo, name, str; double english, math, Java, testScore = 1.0; double sum2 = 0, sum3 = 0; Student s1 = null; Student s2 = null; Student s3 = null; while (in.hasNext()) { String line = in.nextLine(); String[] fields = line.split(" "); //字符串 line 按照空格分隔符进行拆分，拆分后的结果存储在一个名为 fields 的字符串数组中 stuNo = fields[0]; //取 fields 数组的第一个元素，即该语句将 fields 数组的第一个元素的值赋给了变量 stuNo name = fields[1]; english = Double.parseDouble(fields[2]); math = Double.parseDouble(fields[3]); Java = Double.parseDouble(fields[4]); if (fields.length == 5) { // 学生PT s1 = new StudentPT(stuNo, name, english, math, Java, testScore); } else if (fields[5].equals("SystemFramework")) { // 学生SJ s2 = new StudentSJ(stuNo, name, english, math, Java, testScore); sum2 = s2.sum(); } else if (fields[5].equals("GroupLeader")) { // 学生ZZ s3 = new StudentZZ(stuNo, name, english, math, Java, testScore); sum3 = s3.sum(); } else { break; } } //按顺序输出 System.out.println(s1.toString()); System.out.println(s2.toString() + " task:SystemFramework"); System.out.println(s3.toString() + " duty:GroupLeader"); //比较大小 double max = Math.max(sum2,sum3); if(max == sum2){ System.out.println("Lisi's total score is more than Wangwu"); }else if(max == sum3){ System.out.println("Lisi's total score is less than Wangwu"); } } } 在输出时需要再次输入回车才可输出第三组数据，但这不符合要求格式，且后续无法终止输出进程

这是因为你的程序在输入完最后一个学生信息后，需要再次输入回车才能停止循环并输出结果。你可以在输入完最后一个学生信息后，加上一行代码 `break;` 来结束循环，然后直接输出结果即可。修改后的代码如下：

public class StudentDemo { 
    public static void main(String[] args) { 
        Scanner in = new Scanner(System.in); 
        String stuNo, name, str; 
        double english, math, Java, testScore = 1.0; 
        double sum2 = 0, sum3 = 0; 
        Student s1 = null; 
        Student s2 = null; 
        Student s3 = null; 
        while (in.hasNext()) { 
            String line = in.nextLine(); 
            String[] fields = line.split(" "); 
            stuNo = fields[0]; 
            name = fields[1]; 
            english = Double.parseDouble(fields[2]); 
            math = Double.parseDouble(fields[3]); 
            Java = Double.parseDouble(fields[4]); 
            if (fields.length == 5) { 
                s1 = new StudentPT(stuNo, name, english, math, Java, testScore); 
            } else if (fields[5].equals("SystemFramework")) { 
                s2 = new StudentSJ(stuNo, name, english, math, Java, testScore); 
                sum2 = s2.sum(); 
            } else if (fields[5].equals("GroupLeader")) { 
                s3 = new StudentZZ(stuNo, name, english, math, Java, testScore); 
                sum3 = s3.sum(); 
            } else { 
                break; // 结束循环 
            } 
        } 
        System.out.println(s1.toString()); 
        System.out.println(s2.toString() + " task:SystemFramework"); 
        System.out.println(s3.toString() + " duty:GroupLeader"); 
        double max = Math.max(sum2,sum3); 
        if(max == sum2){ 
            System.out.println("Lisi's total score is more than Wangwu"); 
        }else if(max == sum3){ 
            System.out.println("Lisi's total score is less than Wangwu"); 
        } 
    } 
} 

这样修改后，你可以直接输入所有学生信息，程序会自动结束循环并输出结果。