08-02 文件IO流 网络通信（TCP） 集合 泛型

文件写入、读出

public class Test {    public static void main(String[] args) {        File file=new File("d://s.txt");        //写入文件        try {            FileOutputStream fos=new FileOutputStream(file);            OutputStreamWriter writer=new OutputStreamWriter(fos);            BufferedWriter bw=new BufferedWriter(writer);            bw.write("九步踏天");            bw.flush();            bw.close();            writer.close();            fos.close();        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        //读出文件        try {            FileInputStream fis=new FileInputStream(file);//读字节            InputStreamReader reader=new InputStreamReader(fis);//读字符            BufferedReader br=new BufferedReader(reader);//读行            String line=br.readLine();            while(line!=null){                System.out.println(line);                line=br.readLine();             }            br.close();            reader.close();            fis.close();        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

文件复制

public class Test {    public static void main(String[] args) {        File file=new File("d://s.txt");        File filecopy=new File("d://a.txt");        try {            FileInputStream fis=new FileInputStream(file);            FileOutputStream fos=new FileOutputStream(filecopy);            byte[] array=new byte[1024];            int i=fis.read(array);            while(i!=-1){                fos.write(array, 0, i);                i=fis.read();            }            fos.flush();            fos.close();            fis.close();        } catch (FileNotFoundException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

IP地址

public class Test {    public static void main(String[] args) {        try {            InetAddress  address=InetAddress.getLocalHost();            //获取主机名            System.out.println("主机名："+address.getHostName());            //获取IP地址            System.out.println("IP地址："+address.getHostAddress());        } catch (UnknownHostException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

客户端、服务器

//客户端（Client）public class MyClient {    public static void main(String[] args) {        try {            Socket socket=new Socket("192.168.0.141", 8080);            System.out.println("客户端启动");            InputStream is=socket.getInputStream();            InputStreamReader isr=new InputStreamReader(is);            BufferedReader br=new BufferedReader(isr);//客户端输入流            OutputStream os=socket.getOutputStream();            OutputStreamWriter osw=new OutputStreamWriter(os);            BufferedWriter bw=new BufferedWriter(osw);//客户端输出流            Scanner scanner=new Scanner(System.in);            while(true){                String s=scanner.next();//等待控制台输入                bw.write(s+"\n");//向服务器发送数据                bw.flush();//输出完冲涮缓冲区                String back=br.readLine();//等待服务器来数据                System.out.println("服务器："+back);//打印服务器数据            }           } catch (UnknownHostException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}//服务器（Server）public class MyServer {    public static void main(String[] args) {        try {            ServerSocket server=new ServerSocket(8080);            System.out.println("服务器启动");            Socket socket=server.accept();//等待客户端请求            InputStream is=socket.getInputStream();            InputStreamReader isr=new InputStreamReader(is);            BufferedReader br=new BufferedReader(isr);//服务器端输入流            OutputStream os=socket.getOutputStream();            OutputStreamWriter osw=new OutputStreamWriter(os);            BufferedWriter bw=new BufferedWriter(osw);//服务器端输出流            Scanner scanner=new Scanner(System.in);            while(true){                String s=br.readLine();//等待客户端来数据                System.out.println("客户端："+s);//输出客户端的数据                String back=scanner.next();//等待控制台输入                bw.write(back+"\n");//向客户端发送数据                bw.flush();//输出记录冲刷             }           } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

集合

public class Test {    public static void main(String[] args) {        //ArrayList、Set        ArrayList<String> list1=new ArrayList<>();        list1.add("a");        list1.add("b");        list1.add("c");        list1.add("b");        list1.add(1, "d");        System.out.println(list1.get(0));        System.out.println(list1.indexOf("b"));        System.out.println(list1.lastIndexOf("b"));        for (int i = 0; i < list1.size(); i++) {            System.out.println(list1.get(i));           }        System.out.println(list1.contains("a"));        ArrayList<String> list2=new ArrayList<>();        list2.addAll(list1);        list2.remove(0);        list2.remove("a");        for (int i = 0; i < list2.size(); i++) {            System.out.println(list2.get(i));           }        HashSet<Integer> set=new HashSet<>();        Random random=new Random();        int count=0;        while(set.size()<10){            int i=random.nextInt(90);            System.out.println(count+++" " +"随机得到数据："+i);            set.add(i);        }        Iterator<Integer> it=set.iterator();        while(it.hasNext()){            int i=it.next();            System.out.println(i);        }        System.out.println("已经放进去了"+set.size());        HashSet<String> set1=new HashSet<>();        set1.add("a");        set1.add("b");        for(String s:set1){            System.out.println(s);        }        //Map遍历        /*        //有参数的构造器        public Student(String name){            this.name=name;        }        */        HashMap<String, Student> map=new HashMap<>();        Student zhangsan=new Student("张三");        String name="张三";        map.put(name, zhangsan);        map.put(null, new Student("key是空的"));        map.put("lisi",new Student("李斯"));        map.put("wangwu", new Student("王五"));        System.out.println(map.size());        Set<String> keys=map.keySet();        Iterator<String> it=keys.iterator();        while(it.hasNext()){            String key=it.next();            Student stu=map.get(key);            System.out.println(stu.getName());        }        //Collection排序         /*        //有参数的构造器        public Student(String name,int age){            this.name=name;            this.age=age;        }        */        ArrayList<Student> clazz1=new ArrayList<>();        clazz1.add(new Student("张三",18));        clazz1.add(new Student("李斯",23));        clazz1.add(new Student("王五",21));        clazz1.add(new Student("小明",17));        clazz1.add(new Student("小红",22));        Collections.sort(clazz1,new StuComparator());        for(Student stu:clazz1){           System.out.println(stu.getName()+stu.getAge());        }public class StuComparator implements Comparator<Student>{    @Override    public int compare(Student stu1, Student stu2) {        return stu1.getAge()-stu2.getAge();    }   }

泛型

public class NanZhuang {}public class NvZhuang {}public class Cat extends Pat{    public void voice(){        System.out.println("喵喵");    }}public class Dog extends Pat{    public void voice(){        System.out.println("汪汪");    }}public class Pat {}public class Teacher<T,E> {    private String name;    private int age;    private T clothes;    private E pat;    public T getClothes() {        return clothes;    }    public void setClothes(T clothes) {        this.clothes = clothes;    }    public E getPat() {        return pat;    }    public void setPat(E pat) {        this.pat = pat;    }    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 class Test {    public static void main(String[] args) {        Teacher<NanZhuang,Dog> lisi=new Teacher<>();        NanZhuang nan=new NanZhuang();        lisi.setName("李斯");        lisi.setAge(18);        lisi.setClothes(nan);        lisi.setPat(new Dog());        lisi.getPat();        Dog dog=lisi.getPat();    }}