黑马程序员_王康把输入的学生成绩倒叙排列,并存入文本文件中 .

 

//把输入的学生成绩倒叙排列,并存入文本文件中package com.io;/*** * @author 黑马_王康**/public class Student implements Comparable<Student>{        private String name;                private int mt,cn,en;                private int sum;                Student( String name,int mt,int cn,int en){                this.name = name;                this.mt = mt;                this.cn = cn;                this.en = en;                sum = mt + cn + en;        }                public String getName(){                return name;        }                public int getSum(){                return sum;        }                public int getEn(){                return en;        }                public int getCn(){                return cn;        }                @Override        public int compareTo(Student stu) {        //实现compareTo方法                int num = new Integer(this.sum).compareTo(new Integer(stu.sum));                if(num == 0){                        return this.name.compareTo(stu.name);                }                return num;        }                public int hashCode(){        //覆盖hashCode方法                return name.hashCode()+sum*66;        }                public boolean equals(Object obj){        //覆盖equals方法                if(!(obj instanceof Student))                        throw new ClassCastException("类型不匹配");                Student stu = (Student)obj;                return this.name.equals(stu.name)&&this.sum==stu.sum;                        }                public String toString(){        //重写toString方法                return "student["+name+","+mt+","+cn+","+en+"]";        }}package com.io;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.FileWriter;import java.io.IOException;import java.io.InputStreamReader;import java.util.Comparator;import java.util.Set;import java.util.TreeSet;/*** * @author 王康**/public class StudentInfo {        public static Set<Student> getStudents() throws IOException{                return getStudents(null);        }        public static Set<Student> getStudents(Comparator<Student> cmp) throws IOException{        //传一个比较器参数,自定义比较器.                BufferedReader buf = new BufferedReader(new InputStreamReader(System.in)); //读入键盘输入                String line = null;                Set<Student> stus = null;                if(cmp == null)        //判断所使用的比较器                        stus = new TreeSet<Student>();                else        //判断所使用的比较器                        stus = new TreeSet<Student>(cmp);                while((line=buf.readLine()) != null){                        if("over".equals(line))                                break;                        String[] info = line.split(",");        //分割字符串                        Student stu = new Student(info[0], Integer.parseInt(info[1]), Integer.parseInt(info[2]), Integer.parseInt(info[3]));                        stus.add(stu);                }                buf.close();                return stus;        }                public static  void Write2File(Set<Student> stu) throws IOException{                BufferedWriter bw = new BufferedWriter(new FileWriter("D:/testStudent.txt"));        //创建输入流,并建立接受文件                for (Student s : stu) {                        bw.write(s.toString()+"\t");                        bw.write(s.getSum()+"");                        bw.newLine();                        bw.flush();                }                bw.close();        }}package com.io;import java.io.IOException;import java.util.Collections;import java.util.Comparator;import java.util.Set;/*** 测试类* @author 王康**/public class StudentInfoTest {        /**         * @param args         * @throws IOException          */        public static void main(String[] args) throws IOException {                Comparator<Student> cstu = Collections.reverseOrder();        //定义比较器                                Set<Student> stu = StudentInfo.getStudents(cstu);                                StudentInfo.Write2File(stu);        }}启动程序:并输入如下lisi,32,43,54wangwu,56,77,45zhaoliu,54,66,76zhouqi,54,88,91sunba,87,90,83在D:/testStudent.txt会得到文本文件,内容如下:student[sunba,87,90,83]        260student[zhouqi,54,88,91]        233student[zhaoliu,54,66,76]        196student[wangwu,56,77,45]        178