流的操作练习

　　学生信息存储在TXT文件中，学生的每个信息通过空格分开，一个学生信息独占一行存储。

　　我们需要对信息进行基本的,增、删、改、查，全部显示操作。

学生类/Student

package com.fr.Text;

public class Student {
    /** 学生id */
    private int id;
    /** 学生姓名 */
    private String name;
    /** 学生年龄 */
    private int age;
    /** 学生性别 */
    private String sex;

    /**
     * 无参构造方法
     */
    public Student() {
    }

    /**
     * 有参构造方法
     */
    public Student(int id, String name, int age, String sex) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    /**
     * 重写的toString方法
     */
    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", age=" + age + ", sex=" + sex + "]";
    }

    /**
     * 重写的hashCode方法
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((sex == null) ? 0 : sex.hashCode());
        return result;
    }

    /**
     * 重写的equals方法
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Student other = (Student) obj;
        if (age != other.age)
            return false;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (sex == null) {
            if (other.sex != null)
                return false;
        } else if (!sex.equals(other.sex))
            return false;
        return true;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

}

学生管理类的接口定义/StudentManagement

package com.fr.Text;

import java.io.File;
import java.util.List;

public interface StudentManagement {
    /** 默认路径 */
    public static final String DEFAULT_PATH = System.getProperty("user.dir") + File.separator + "Student.txt";

    /**
     * 取出文件中所有学生的信息
     * 
     * @return 学生类的集合,如果文件中没有就返回null
     */
    public List<Student> list();

    /**
     * 向文件中添加一个学生信息， 如果文件中已经存在传入对象的id则添加失败。
     * 
     * @param student
     *            学生的对象
     * @return 添加成功返回true,添加失败返回false
     */
    public boolean increase(Student student);

    /**
     * 根据输入的id删除文件中的学生信息
     * 
     * @param id
     *            学生的id值
     * @return true/删除成功 false/删除失败或者文件中没有该学生id
     */
    public boolean delete(int id);

    /**
     * 修改学生的属性，根据传入学生的id值，查找学生，然后将新学生数据替换此数据
     * 
     * @param student
     *            学生的对象
     * @return true/修改成功 false/修改失败，或者文件中没有该学生id的学生
     */
    public boolean change(Student student);

    /**
     * 根据传入的id，在文件中查找学生的属性
     * 
     * @param id
     *            学生的id
     * @return 对应id的学生对象，没有则返回null
     */
    public Student CheckId(int id);

    /**
     * 根据传入对象的数据查找是否有该对象
     * 
     * @param student
     *            学生对象
     * @return true/找到返回 false/没找到
     */
    public boolean CheckStudent(Student student);
}

学生管理类接口的实现类/MyStudentManagement

package com.fr.Text;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

public class MyStudentManagement implements StudentManagement {
    /** 文件路径 */
    private String CustomPath;

    /**
     * 默认路径下查找文件， 如果没有找到就创建一个
     */
    public MyStudentManagement() {
        this.CustomPath = DEFAULT_PATH;
        File file = null;
        try {
            file = new File(this.CustomPath);
            if (!(file.exists())) {
                file.createNewFile();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 自定义路径下查找文件， 如果没有找到就创建一个
     */
    public MyStudentManagement(String CustomPath) {
        this.CustomPath = CustomPath;
        File file = null;
        try {
            file = new File(this.CustomPath);
            if (!(file.exists())) {
                file.createNewFile();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public List<Student> list() {
        List<Student> lists = new ArrayList<>();
        BufferedReader bis = null;
        try {
            bis = new BufferedReader(new FileReader(this.CustomPath));
            String str = null;
            while ((str = bis.readLine()) != null) {
                String[] stus = str.split("\s+");
                lists.add(new Student(new Integer(stus[0]), stus[1], new Integer(stus[2]), stus[3]));
            }
            return lists;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

    @Override
    public boolean increase(Student student) {
        boolean flag = false;
        PrintWriter pw = null;
        try {
            pw = new PrintWriter(new FileOutputStream(CustomPath, true));
            List<Student> lists = list();
            for (int i = 0; i < lists.size(); i++) {
                if (lists.get(i).getId() == student.getId()) {
                    return false;
                }
            }
            pw.println((student.getId() + " " + student.getName() + " " + student.getAge() + " " + student.getSex()));
            flag = true;
        } catch (FileNotFoundException e) {
            flag = false;
            e.printStackTrace();
        } finally {
            try {
                if (pw != null) {
                    pw.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return flag;
    }

    @Override
    public boolean delete(int id) {
        boolean flag = false;
        PrintWriter pw = null;
        try {
            List<Student> lists = list();
            for (int i = 0; i < lists.size(); i++) {
                Student student = lists.get(i);
                if (student.getId() == id) {
                    lists.remove(student);
                    flag = true;
                    break;
                }
            }
            if (flag) {
                pw = new PrintWriter(CustomPath);
                for (int i = 0; i < lists.size(); i++) {
                    Student student = lists.get(i);
                    pw.println((student.getId() + " " + student.getName() + " " + student.getAge() + " "
                            + student.getSex()));
                }
            }
        } catch (FileNotFoundException e) {
            flag = false;
            e.printStackTrace();
        } finally {
            try {
                if (pw != null) {
                    pw.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return flag;
    }

    @Override
    public boolean change(Student student) {
        boolean flag = false;
        PrintWriter pw = null;
        try {

            List<Student> lists = list();
            for (int i = 0; i < lists.size(); i++) {
                if (lists.get(i).getId() == student.getId()) {
                    lists.get(i).setName(student.getName());
                    lists.get(i).setAge(student.getAge());
                    lists.get(i).setSex(student.getSex());
                    flag = true;
                    break;
                }
            }
            if (flag) {
                pw = new PrintWriter(CustomPath);
                for (int i = 0; i < lists.size(); i++) {
                    increase(lists.get(i));
                }
            }

        } catch (FileNotFoundException e) {
            flag = false;
            e.printStackTrace();
        } finally {
            try {
                if (pw != null) {
                    pw.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return flag;
    }

    @Override
    public Student CheckId(int id) {
        List<Student> lists = list();
        for (int i = 0; i < lists.size(); i++) {
            if (lists.get(i).getId() == id) {
                return lists.get(i);
            }
        }
        return null;
    }

    @Override
    public boolean CheckStudent(Student student) {
        List<Student> lists = list();
        for (int i = 0; i < lists.size(); i++) {
            if (student.equals(lists.get(i))) {
                return true;
            }
        }
        return false;
    }

}