java io 根据TXT 在控制台上输出相关表的信息

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class TestCut {
    /**
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        TestCut test = new TestCut();
        List<Student> list = test.readFile("D:\\Students.txt", "GBK");
        test.printAver(list);
        System.out.println("-------------------------------------------");
        test.printExcel(list);
        System.out.println("---------------------------------------------");
        test.printEnglishAvg(list);
    }
    /**
     * 按照平均分降序格式化输出
     *
     * @param list
     */
    public void printAver(List<Student> list) {
        if (list != null) {
            String top = "序号\t学号\t平均分\t数学\t语文\t英语";
            System.out.println(top);
            Collections.sort(list, new Comparator<Student>() {
                // 根据平均数来进行比较,降序排序
                public int compare(Student arg0, Student arg1) {
                    if (arg1 == null)
                        return -1;
                    if (arg0.getAvg() < arg1.getAvg())
                        return 1;
                    else if (arg0.getAvg() == arg1.getAvg())
                        return 0;
                    else
                        return -1;
                }
            });
            for (int i = 0; i < list.size(); i++) {
                Student student = list.get(i);
                System.out.print((i + 1) + "\t" + student.getS_no() + "\t"
                        + student.getAvg() + "\t");
                System.out.print(student.getMaths() + "\t"
                        + student.getChinese() + "\t");
                if (student.getEnglish() != null)
                    System.out.println(student.getEnglish());
                else {
                    System.out.println();
                }
            }
        } else {
            System.out.println("文件内容为空!");
        }
    }
    /**
     * 按照优秀率格式化输出
     *
     * @param list
     */
    public void printExcel(List<Student> list) {
        if (list != null) {
            String top = "序号\t学号\t优秀率\t数学\t语文\t英语";
            System.out.println(top);
            Collections.sort(list, new Comparator<Student>() {
                // 根据优秀率来进行比较,降序排序
                public int compare(Student arg0, Student arg1) {
                    if (arg1 == null)
                        return -1;
                    if (arg0.getExcel() < arg1.getExcel())
                        return 1;
                    else if (arg0.getExcel() == arg1.getExcel())
                        return 0;
                    else
                        return -1;
                }
            });
            for (int i = 0; i < list.size(); i++) {
                Student student = list.get(i);
                DecimalFormat df = new DecimalFormat("#%");
                System.out.print((i + 1) + "\t" + student.getS_no() + "\t"
                        + df.format(student.getExcel()) + "\t");
                System.out.print(student.getMaths() + "\t"
                        + student.getChinese() + "\t");
                if (student.getEnglish() != null)
                    System.out.println(student.getEnglish());
                else {
                    System.out.println();
                }
            }
        } else {
            System.out.println("文件内容为空!");
        }
    }
    /**
     * 求英语平均成绩
     * @param list
     */
    public void printEnglishAvg(List<Student> list) {
        printAvgByCourse(list, 3);
    }
    /**
     * 求课程平均成绩,并输出
     *
     * @param list
     * @param course
     *        课程(1:数学,2:语文,3:英语)
     */
    private void printAvgByCourse(List<Student> list, int course) {
        Integer avg = 0;
        switch (course) {
        case 1: {
            Integer maths = 0;
            for (Student student : list) {
                maths += student.getMaths();
            }
            avg = maths / list.size();
            System.out.println("数学平均成绩：\t" + avg);
            break;
        }
        case 2: {
            Integer chinese = 0;
            for (Student student : list) {
                chinese += student.getChinese();
            }
            avg = chinese / list.size();
            System.out.println("语文平均成绩：\t" + avg);
            break;
        }
        case 3: {
            Integer english = 0;
            Integer size = 0;
            for (Student student : list) {
                if (student.getEnglish() != null) {
                    english += student.getEnglish();
                    size++;
                }
            }
            if (size != 0)
                avg = english / size;
            System.out.println("英语平均成绩：\t" + avg);
            break;
        }
        default: {
            System.out.println("不存在此课程");
            break;
        }
        }
    }
    /**
     * 读取文件信息
     *
     * @param fileName
     *            文件路径
     * @param charset
     *            编码
     * @return
     * @throws IOException
     */
    public List<Student> readFile(String fileName, String charset) {
        List<Student> list = new ArrayList<Student>();
        FileInputStream fi = null;
        BufferedReader in = null;
        try {
            fi = new FileInputStream(new File(fileName));
            in = new BufferedReader(new InputStreamReader(fi, charset));
            String result = in.readLine();
            while ((result = in.readLine()) != null) {
                String[] str = result.split("\t");
                Student student = new Student();
                for (int i = 0; i < str.length; i++) {
                    student.setS_no(str[0]);
                    student.setMaths(Integer.parseInt(str[1]));
                    student.setChinese(Integer.parseInt(str[2]));
                    if (str.length > 3) {
                        student.setEnglish(Integer.parseInt(str[3]));
                    }
                    student.setAvg(student.culAvg());
                    student.setExcel(student.culExcel());
                }
                list.add(student);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return list;
    }
}
class Student implements Serializable {
    private static final long serialVersionUID = -6517638655032546653L;
    /**
     * 学号
     */
    private String s_no;
    /**
     * 数学
     */
    private Integer maths;
    /**
     * 语文
     */
    private Integer chinese;
    /**
     * 英语
     */
    private Integer english;
    /**
     * 平均分
     */
    private Integer avg;
    /**
     * 优秀率
     */
    private float excel;
    public Student() {
    }
    public Student(Integer maths, Integer chinese, Integer english) {
        this.maths = maths;
        this.chinese = chinese;
        this.english = english;
        this.avg = culAvg(maths, chinese, english);
        this.excel = culExcel(maths, chinese, english);
    }
    public String getS_no() {
        return s_no;
    }
    public void setS_no(String sNo) {
        s_no = sNo;
    }
    public Integer getMaths() {
        return maths;
    }
    public void setMaths(Integer maths) {
        this.maths = maths;
    }
    public Integer getChinese() {
        return chinese;
    }
    public void setChinese(Integer chinese) {
        this.chinese = chinese;
    }
    public Integer getEnglish() {
        return english;
    }
    public void setEnglish(Integer english) {
        this.english = english;
    }
    public Integer getAvg() {
        return avg;
    }
    public void setAvg(Integer avg) {
        this.avg = avg;
    }
    public float getExcel() {
        return excel;
    }
    public void setExcel(float excel) {
        this.excel = excel;
    }
    public String toString() {
        StringBuffer sb = new StringBuffer("[");
        sb.append("s_no=" + s_no).append(",maths=").append(maths).append(
                ",chinese=").append(chinese).append(",english=")
                .append(english).append(",avg=").append(avg).append(",excel=")
                .append(excel).append("]");
        return sb.toString();
    }
    /**
     * 计算平均数
     *
     * @param maths
     *            数学
     * @param chinese
     *            语文
     * @param english
     *            英语
     * @return
     */
    private Integer culAvg(Integer maths, Integer chinese, Integer english) {
        // 计算平均分
        Integer sum = chinese + maths;
        float aver = english == null ? (float) sum / 2
                : (float) (sum + english) / 3;
        return Math.round(aver);
    }
    /**
     * 计算优秀率
     *
     * @param maths
     *            数学
     * @param chinese
     *            语文
     * @param english
     *            英语
     * @return
     */
    private float culExcel(Integer maths, Integer chinese, Integer english) {
        final Integer EXCEL_NUMBER = 85;
        Integer total_number = english == null ? 2 : 3;
        Integer ex = 0;
        if (maths >= EXCEL_NUMBER)
            ex++;
        if (chinese >= EXCEL_NUMBER)
            ex++;
        if (english != null && english >= EXCEL_NUMBER)
            ex++;
        return (float) ex / total_number;
    }
    /**
     * 计算平均数
     *
     * @return
     */
    public Integer culAvg() {
        return culAvg(this.maths, this.chinese, this.english);
    }
    /**
     * 计算优秀率
     *
     * @return
     */
    public float culExcel() {
        return culExcel(this.maths, this.chinese, this.english);
    }
}

本文出自seven的测试人生公众号最新内容请见作者的GitHub页：http://qaseven.github.io/