字符流

范例：
public class PetDemo {
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = null;
        BufferedReader br = null;
        BufferedWriter modify_bw = null;
        try {
            //1.创建模板文件
            bw = new BufferedWriter(new FileWriter(new File("E:\Java实训课总结\2016.3.26" + File.separator + "pet.template")));
            bw.write("替换前：");
            bw.append("您好！我的名字是{name}，我是一只{type}。我的主人是{master}。");
            bw.flush();
            //2.读取模板文件的信息
            br = new BufferedReader(new FileReader("E:\Java实训课总结\2016.3.26" + File.separator + "pet.template"));
            String line = br.readLine(); ★★★同一个对象，readLine每用到一次 ，就是一行！！！★★★
            System.out.println(line);
            //3.替换文件信息后，写入新的文本文件中
            String modify_line = line;
            modify_line = line.replace("替换前：", "替换后：");
            ★★★每次更新内容就赋值一次！！！★★★
            modify_line = modify_line.replace("{name}", "lili");
            modify_line = modify_line.replace("{type}", "拉布拉多");
            modify_line = modify_line.replace("{master}", "王刚");
            System.out.println(modify_line);
            modify_bw = new BufferedWriter(new FileWriter(new File("E:\Java实训课总结\2016.3.26" + File.separator + "pet.txt")));
            modify_bw.append(modify_line);
            modify_bw.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            modify_bw.close();
            br.close();
            bw.close();
        }
    }
}


范例1：/*方法1：UUID*/
public class FileMethodDemo {
    public void creatFileFolder(String path) throws IOException{
        File file = new File(path);
        if (!file.exists()) {
            //创建文件夹
            file.mkdir();
            System.out.println("创建文件成功！");
        }
    }
    
    public void creatFile(String fileName) throws IOException{
        File file = new File(fileName);
        if (!file.exists()) {
            //创建文件
            file.createNewFile();
            System.out.println("创建文件成功！");
        }
    }
    
    //删除文件
    public void delFile(String fileName){
        File file = new File(fileName);
        if (file.exists()) {
            file.delete();
            System.out.println("删除文件成功！");
        }
    }
    
    //清理文件
    public void delAllFile(String path){
        File file = new File(path);
        if (file.exists()) {
            file.delete();
        }
    }
}

//测试
public class D_demotxt {
    public static void main(String[] args) throws IOException {
        FileMethodDemo fm = new FileMethodDemo();    //调用FileMethodDemo中的方法
        String path = "E:\Java实训课总结\2016.3.25\Demo100";
        //清理文件中的已有的文件
        fm.delAllFile(path);
        try {
            //1.创建文件夹
            fm.creatFileFolder(path);
            //2.创建文件
            ArrayList<String> nameArr = new ArrayList<String>();
            //随机唯一的名字，放在集合中
            for (int i = 0; i < 100; i++) {
                UUID uuid = UUID.randomUUID();
                String fileName = uuid.toString();
                nameArr.add(fileName);
            }
            
            //3.生成100个文件名字
            for (int i = 0; i < nameArr.size(); i++) {
                String filepath = path + File.separator + nameArr.get(i) + ".txt";
                fm.creatFile(filepath);
            }
            
            //3.找出开头a的文件
            for (int i = 0; i < 100; i++) {
                if (nameArr.get(i).startsWith("a")) {
                    String str = path + File.separator + nameArr.get(i) + ".txt";
                    fm.delFile(str);
                    System.out.println(str);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }    
}


范例1：/*方法2：Map*/
/*学生类*/
public class Student {
    private String name;
    private String[] xin = new String[]{"丁","王","徐","汤","独孤","李"};
    private String[] ming = new String[]{"强","求败","建国","援朝","翠花","狗蛋","嫚","凯","程琳"};
    
    public Student(){
        Random rd = new Random();
        this.name = xin[rd.nextInt(xin.length)] + ming[rd.nextInt(ming.length)];
    }
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

/*测试类*/
public class ImproveDulName {
    public static void main(String[] args){
        Map<Integer, Student> map = new HashMap<Integer, Student>();
        /*存数据*/
        for (int i = 0; i <= 15; i++) {
            map.put(i, new Student());
        }
        //标识重复的名字
        String dulName = null;
        for (int j = 0; j < map.size(); j++) {
            for (int j2 = j+1; j2 < map.size(); j2++) {
                if (map.get(j).getName().equals(map.get(j2).getName())) {
                    map.get(j).setName(map.get(j).getName() + "*");
                    map.put(j, map.get(j));
                    if (map.get(j2).getName().startsWith("徐")) {
                        System.out.println("学号：" + (j2 + 1) + "," + map.get(j2).getName());
                    }
                    break;
                } else{
                    map.put(j, map.get(j));
                }
            }
        }
    
        //构建字符流对象
        BufferedWriter bw = null;
        try {
            bw = new BufferedWriter(new FileWriter("E:\Java实训课总结\2016.3.24\ImprovedulplicateName.txt"));
            for (int j = 0; j < map.size(); j++) {
                bw.append("学号：" + (j + 1) + "," + map.get(j).getName());
                bw.newLine();
                bw.flush();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                bw.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }    
}


范例1：/*方法3：重复3次以上的名字打星号*/
/*学生类*/
public class Student {
    private String familyName;
    private String givenName;
    private int flag;//重名的标记
    private String name;
    private int count;
    
    public Student(){
        //随机填充一个名字
        Random rd = new Random();
        this.familyName = MyUtil.familyName[rd.nextInt(MyUtil.familyName.length)];
        this.givenName = MyUtil.givenName[rd.nextInt(MyUtil.givenName.length)];
        this.flag = 0;//假设初始的状态都不同
        this.name = this.familyName + this.givenName;
        this.count = 1;
    }

    public Student(String familyName, String givenName, int flag) {
        this.familyName = familyName;
        this.givenName = givenName;
        this.flag = flag;
        this.name = this.familyName + this.givenName;
        this.count = 1;
    }
    
    @Override
    public String toString() {
        return "Student [familyName=" + familyName + ", givenName=" + givenName + ", flag=" + flag + ", name=" + name
                + ", count=" + count + "]";
    }

    public String getName() {
        return name;
    }
    public void setName() {
        this.name = this.familyName + this.givenName;
    }
    public String getFamilyName() {
        return familyName;
    }
    public void setFamilyName(String familyName) {
        this.familyName = familyName;
    }
    public String getGivenName() {
        return givenName;
    }
    public void setGivenName(String givenName) {
        this.givenName = givenName;
    }
    public int getFlag() {
        return flag;
    }
    public void setFlag(int flag) {
        this.flag = flag;
    }
    public int getCount() {
        return count;
    }
    public void setCount(int count) {
        this.count = count;
    }

    //测试
    public static void main(String[] args) {
        List<Student> al = new ArrayList<Student>();
        for (int i = 0; i < 50; i++) {
            Student stu = new Student();
            al.add(stu);
            System.out.println(stu);
        }
        
        StudentOP sop = new StudentOP();
//        sop.changeFlagforDulName(al);
        sop.changeFlagforThrName(al);
        //测试修改成功与否
        for (Student stu : al) {
            System.out.println(stu);
        }
        
        //测试写文件
        sop.WriteToTxt(al);
    }
}
/*学生操作类*/
public class StudentOP {
    //1.对学生对象的姓名重复的，把flag重置为1
    public void changeFlagforDulName(List<Student> stuArr){
        //遍历数组，把重名的flag重置为1
        for (int i = 0; i < stuArr.size(); i++) {
            for (int j = i + 1; j < stuArr.size(); j++) {
                if (stuArr.get(i).getName().equals(stuArr.get(j).getName())) {
                    stuArr.get(i).setFlag(1);
//                    stuArr.get(j).setFlag(1);
                }
            }
        }
    }
    
    //2.重复三次的姓名标记
    public void changeFlagforThrName(List<Student> stuArr){
        //遍历数组，把重名的flag重置为1
        changeFlagforDulName(stuArr);
        for (int i = 0; i < stuArr.size(); i++) {
            int count = stuArr.get(i).getCount();
            for (int j = i + 1; j < stuArr.size(); j++) {
                if (stuArr.get(i).getName().equals(stuArr.get(j).getName())) {
                    stuArr.get(i).setCount(++count);
                    int my = stuArr.get(i).getCount();
                    stuArr.get(j).setCount(my);
                }
            }
        }
    }
    
    public void WriteToTxt(List<Student> stuArr){
        BufferedWriter bw = null;
        try {
            bw = new BufferedWriter(new FileWriter("E:\Java实训课总结\2016.3.28\100rd_name.txt"));
            for (Student stu : stuArr) {
//                if (stu.getFlag() == 1) {
                if (stu.getCount() == 3) {
                    bw.write(stu.getName() + "*");
                } else {
                    bw.write(stu.getName());
                }
                bw.newLine();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                bw.flush();
                bw.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}
/*随机姓和名类*/
public class MyUtil {
    public static String[] familyName = {"王","李","徐","温","张","刘"};
    public static String[] givenName = {"丽丽","峰","仲基","嫚","学友","佳丽","凯"};
}