JAVA-day12-IO3、反射

import java.io.*;class Demo1 {public static void main(String[] args)throws IOException {/*          PrintStream:打印流，具备字节输出流的基本功能，添加了打印功能  是一个可以向目的写入的输出流  目的：File        字符串形式的路径字节输出流   */PrintStream ps = new PrintStream("tt.txt");        //一次写入一个字节//ps.write(353);//00000000 00000000 00000001 01100001  把低8位的一个字节写入ps.println(353);//按照数据原样儿写入，也就是数据的表现形式，内部使用了转成字符串的功能，String.valueOf()ps.write(String.valueOf(353).getBytes());}}

import java.io.*;class Demo2 {public static void main(String[] args) throws IOException{/*         PrintWriter:字符打印流,字符输出流的基本功能都具备 目的：File       字符串形式的路径   字节输出流   字符数出流*/BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//PrintWriter pw = new PrintWriter(System.out,true);PrintWriter pw2 = new PrintWriter(new FileWriter("t.txt"),true);String line = null;while((line = br.readLine())!=null){if("over".equals(line))break;           pw2.println(line);//pw.flush();}}}

//序列流:SequenceInputStreamimport java.io.*;import java.util.*;class  Demo3{public static void main(String[] args) throws IOException{ /*FileInputStream fis1= new FileInputStream("Demo1.java");FileInputStream fis2= new FileInputStream("Demo2.java");FileInputStream fis3= new FileInputStream("Demo3.java");Vector<FileInputStream> v= new Vector<FileInputStream>();v.add(fis1);v.add(fis2);v.add(fis3);Enumeration<FileInputStream>  en = v.elements();*/ArrayList<FileInputStream> list = new ArrayList<FileInputStream>();        for(int i=1;i<=3;i++){list.add(new FileInputStream("Demo"+i+".java"));}Enumeration<FileInputStream> en = Collections.enumeration(list);SequenceInputStream sis = new SequenceInputStream(en);        FileOutputStream fos = new FileOutputStream("hebing2.java");byte[] b = new byte[1024];int len = 0;while((len = sis.read(b))!=-1){fos.write(b,0,len);}sis.close();fos.close();}}

//分割文件import java.io.*;import java.util.*;class  Demo4{public static void main(String[] args)throws IOException {File file = new File("C:\\Users\\qq\\Desktop\\ok.jpg");splitFile(file);}    //分割文件public static void splitFile(File file)throws IOException{    if(!file.isFile()){System.out.println("不是文件");return;}//创建存储被分割出来的文件的目录File dir = new File("fenge");if(!dir.exists())dir.mkdir();FileInputStream fis = new FileInputStream(file);FileOutputStream fos = null;        byte[] arr = new byte[1024*1024*2];int len = 0;        int num = 1;while((len = fis.read(arr))!=-1){fos = new FileOutputStream(new File(dir,(num++)+".suipian"));fos.write(arr,0,len);}              //这几个被分割出来的文件上传之后，使用者不知道文件类型和一共有 //几个分割出的文件，应该把这些信息以配置文件的形式告诉使用者  Properties pro = new Properties(); pro.setProperty("filetype",file.getName()); pro.setProperty("fileNumber",Integer.toString(--num));         fos = new FileOutputStream(new File(dir,"config.properties")); pro.store(fos," ");     fis.close(); fos.close();}}

import java.io.*;class Person implements Serializable//标记接口{static final long serialVersionUID = 42L;private /*static*/ String name;//被静态修饰的成员不参与序列化private  /*transient*/ int age;  //瞬态的成员不参与序列化public Person(){}public Person(String name,int age){this.name = name;this.age = age;}public String getName(){return this.name;}public int getAge(){return this.age;}}class  Demo5{public static void main(String[] args)throws IOException,ClassNotFoundException{//writeObject();        readObject();}    //反序列化 //对象是依赖于其所属的类的，有那个class才会有对象 public static void readObject()throws IOException,ClassNotFoundException{ObjectInputStream ois = new ObjectInputStream(new FileInputStream("obj.txt"));Person person = (Person)ois.readObject();//5964614836505496678    -2747677651716560467System.out.println(person.getName()+","+person.getAge());}//写入对象    //序列化:把一个对象写入到一个目的--对象的持久化public static void writeObject()throws IOException {ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("obj.txt"));oos.writeObject(new Person("lisi",23));//5964614836505496678 Person.classoos.close();}}

import java.io.*;class Demo6 {public static void main(String[] args)throws IOException {/*          RandomeAccessFile:     随机访问文件的流类 只能访问文件 内部既有字节输入流也有字节输出流 内部定义了一个字节数组，并通过指针操作该数组，所以能随机访问 *///writeFile();        //readFile();rw();}public static void rw()throws IOException {    RandomAccessFile  raf = new RandomAccessFile("rw.txt","rw");raf.seek(30);raf.writeUTF("你好");    long index = raf.getFilePointer();    System.out.println("index="+index);        raf.seek(30);String ss = raf.readUTF();System.out.println(ss);}public static void readFile()throws IOException { RandomAccessFile  raf = new RandomAccessFile("temp.txt","r");         byte[] arr = new byte[4]; int len = 0; len = raf.read(arr); int age = raf.readInt(); System.out.println(new String(arr,0,len)+","+age); long index = raf.getFilePointer();     System.out.println("index="+index); raf.seek(15); len = raf.read(arr); age = raf.readInt();         System.out.println(new String(arr,0,len)+","+age);}public static void writeFile()throws IOException{//文件不存在会自动创建   RandomAccessFile  raf = new RandomAccessFile("temp.txt","rw");   raf.write("刘能".getBytes());   raf.writeInt(58);   long index = raf.getFilePointer();//得到指针指向的位置   raf.seek(15);   raf.write("赵四".getBytes());   raf.writeInt(56);   index = raf.getFilePointer();   System.out.println("index="+index);}}

import java.io.*;class  Demo7{public static void main(String[] args)throws IOException {/*用于操作基本数据类型的流类         DataInputStream  DataOutputStream*/writeData();readData();}public static void readData()throws IOException{DataInputStream dis = new DataInputStream(new FileInputStream("data.txt"));int a = dis.readInt();boolean boo = dis.readBoolean();double d = dis.readDouble();System.out.println(a+","+boo+","+d);}public static void writeData()throws IOException{DataOutputStream dos = new DataOutputStream(new FileOutputStream("data.txt"));dos.writeInt(34);dos.writeBoolean(false);dos.writeDouble(45.56);dos.close();}}

import java.io.*;class  Demo8{public static void main(String[] args)throws IOException {/*         内存流： ByteArrayInputStream:内部有一个字节数组 ByteArrayOutputStream: 内部有一个字节数组，直接写入了自己内部的字节数组了        */ByteArrayInputStream du = new ByteArrayInputStream("owieurwoeir".getBytes());ByteArrayOutputStream xie = new ByteArrayOutputStream();byte[] arr = new byte[1024];int len = 0;while((len =du.read(arr))!=-1){xie.write(arr,0,len);}System.out.println(new String(xie.toByteArray()));}}

import java.io.*;import java.util.*;import java.text.*;class Demo10 {public static void main(String[] args) throws IOException{try{int[] arr = new int[3];System.out.println(arr[3]);}catch (Exception e){Date d = new Date();SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd E HH:mm:ss");String ss = sdf.format(d);            PrintStream ps = new PrintStream("bug.txt");ps.println(ss);            System.setOut(ps);e.printStackTrace(System.out);}}}

/*二:有五个学生，每个学生有3门课的成绩，从键盘输入以上数据（包括姓名，三门课成绩），输入的格式：如：zhagnsan，30，40，60计算出总成绩，并把学生的信息和计算出的总分数高低顺序存放在磁盘文件"stud.txt"中。1:描述一下学生2:定义个操作学生的工具类*/import java.io.*;import java.util.*;class Student  implements Comparable<Student>{private String name;private int math,china,eng;private int sum;public Student(){}public Student(String name,int math,int china,int eng){this.name =name;this.math = math;this.china = china;this.eng = eng;sum = math+china+eng;}public int compareTo(Student stu){int num = this.sum-stu.sum;return num==0?this.name.compareTo(stu.name):num;}    public int getSum(){        return this.sum;    }public int getMath(){    return this.math;}public int getChina(){return this.china;}public int getEng(){return this.eng;}    public String toString(){   return "Student["+name+","+math+","+china+","+eng+"]";}}//操作学生的工具类class StuTool{   public static Set<Student> getStudents()    {   return getStudents(null);}//读取键盘录入的学生信息，并存入集合public static Set<Student>  getStudents(Comparator<Student> com)throws IOException{BufferedReader br = new BufferedReader(new InputStreamReader(System.in));TreeSet<Student>   students;if(com!=null)               students = new  TreeSet<Student>(com);else               students = new  TreeSet<Student>();String line = null;for(int i=1;i<=3;i++){   System.out.println("请输入第"+i+"个学员的信息");   line = br.readLine();   String[] arr = line.split(",");   Student stu = new Student(arr[0],Integer.parseInt(arr[1]),Integer.parseInt(arr[2]),Integer.parseInt(arr[3]));           students.add(stu);}return students;}//把学员信息存入文件public static void saveToFile(Set<Student> students)throws IOException{     BufferedWriter  bw = new BufferedWriter(new FileWriter("stud.txt"));          for(Student stu:students) {     bw.write(stu.toString()+"\t"); bw.write(""+stu.getSum()); bw.newLine(); bw.flush(); } bw.close();}}class Demo11 {public static void main(String[] args) throws IOException{Comparator<Student>  com = Collections.reverseOrder();Set<Student>  s = StuTool.getStudents(com);StuTool.saveToFile(s);}}

import  java.io.*;class Demo12 {public static void main(String[] args)throws IOException  {//转换流的编码问题//writeFile();readFile();}    public static void readFile()throws IOException{InputStreamReader isr = new InputStreamReader(new FileInputStream("gbk.txt"),"utf-8");char[] ch = new char[10];int len = 0;len = isr.read(ch);System.out.println(new String(ch,0,len));}public static void writeFile()throws IOException {OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("utf.txt"),"utf-8");osw.write("你好");osw.close();}}

/*编码：家里有事，速回。----》电报文          byte[] getBytes()           使用平台的默认字符集将此 String 编码为 byte 序列    byte[] getBytes(String charsetName)           使用指定的字符集将此 String 编码为 byte 序列 解码：电报文-----》家里有事，速回。      String(byte[] bytes)           通过使用平台的默认字符集解码指定的 byte 数组，构造一个新的 String。      String(byte[] bytes, Charset charset)           通过使用指定的 charset 解码指定的 byte 数组，构造一个新的 String编码编对了,解码就能解对编码编错了，就不可能解对*/import java.util.*;class  Demo13{public static void main(String[] args)throws Exception{String ss ="你好";byte[] b = ss.getBytes("gbk");System.out.println(Arrays.toString(b));        //解码解错了String str = new String(b,"ISO8859-1");System.out.println(str);//解决解码解错了的问题       byte[] arr = str.getBytes("ISO8859-1");       //使用gbk进行解码   String s = new String(arr);   System.out.println(s);}}

class Demo14 {public static void main(String[] args) {String ss = "我的联通";byte[] b = ss.getBytes();for(byte num:b){System.out.println(Integer.toBinaryString(num&255));}}}

import java.io.*;class Demo1 {public static void main(String[] args)throws IOException {/*          PrintStream:打印流，具备字节输出流的基本功能，添加了打印功能  是一个可以向目的写入的输出流  目的：File        字符串形式的路径字节输出流   */PrintStream ps = new PrintStream("tt.txt");        //一次写入一个字节//ps.write(353);//00000000 00000000 00000001 01100001  把低8位的一个字节写入ps.println(353);//按照数据原样儿写入，也就是数据的表现形式，内部使用了转成字符串的功能，String.valueOf()ps.write(String.valueOf(353).getBytes());}}import java.io.*;class Demo2 {public static void main(String[] args) throws IOException{/*         PrintWriter:字符打印流,字符输出流的基本功能都具备 目的：File       字符串形式的路径   字节输出流   字符数出流*/BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//PrintWriter pw = new PrintWriter(System.out,true);PrintWriter pw2 = new PrintWriter(new FileWriter("t.txt"),true);String line = null;while((line = br.readLine())!=null){if("over".equals(line))break;           pw2.println(line);//pw.flush();}}}//序列流:SequenceInputStreamimport java.io.*;import java.util.*;class  Demo3{public static void main(String[] args) throws IOException{FileInputStream fis1= new FileInputStream("Demo1.java");FileInputStream fis2= new FileInputStream("Demo2.java");FileInputStream fis3= new FileInputStream("Demo3.java");Vector<FileInputStream> v= new Vector<FileInputStream>();v.add(fis1);v.add(fis2);v.add(fis3);Enumeration<FileInputStream>  en = v.elements();SequenceInputStream sis = new SequenceInputStream(en);        FileOutputStream fos = new FileOutputStream("hebing.java");byte[] b = new byte[1024];int len = 0;while((len = sis.read(b))!=-1){fos.write(b,0,len);}sis.close();fos.close();}}

import java.io.*;class Demo1 {public static void main(String[] args)throws IOException {/*          PrintStream:打印流，具备字节输出流的基本功能，添加了打印功能  是一个可以向目的写入的输出流  目的：File        字符串形式的路径字节输出流   */PrintStream ps = new PrintStream("tt.txt");        //一次写入一个字节//ps.write(353);//00000000 00000000 00000001 01100001  把低8位的一个字节写入ps.println(353);//按照数据原样儿写入，也就是数据的表现形式，内部使用了转成字符串的功能，String.valueOf()ps.write(String.valueOf(353).getBytes());}}import java.io.*;class Demo2 {public static void main(String[] args) throws IOException{/*         PrintWriter:字符打印流,字符输出流的基本功能都具备 目的：File       字符串形式的路径   字节输出流   字符数出流*/BufferedReader br = new BufferedReader(new InputStreamReader(System.in));//PrintWriter pw = new PrintWriter(System.out,true);PrintWriter pw2 = new PrintWriter(new FileWriter("t.txt"),true);String line = null;while((line = br.readLine())!=null){if("over".equals(line))break;           pw2.println(line);//pw.flush();}}}//序列流:SequenceInputStreamimport java.io.*;import java.util.*;class  Demo3{public static void main(String[] args) throws IOException{ /*FileInputStream fis1= new FileInputStream("Demo1.java");FileInputStream fis2= new FileInputStream("Demo2.java");FileInputStream fis3= new FileInputStream("Demo3.java");Vector<FileInputStream> v= new Vector<FileInputStream>();v.add(fis1);v.add(fis2);v.add(fis3);Enumeration<FileInputStream>  en = v.elements();*/ArrayList<FileInputStream> list = new ArrayList<FileInputStream>();        for(int i=1;i<=3;i++){list.add(new FileInputStream("Demo"+i+".java"));}Enumeration<FileInputStream> en = Collections.enumeration(list);SequenceInputStream sis = new SequenceInputStream(en);        FileOutputStream fos = new FileOutputStream("hebing2.java");byte[] b = new byte[1024];int len = 0;while((len = sis.read(b))!=-1){fos.write(b,0,len);}sis.close();fos.close();}}

反射

package com.qianfeng.reflect;public class Demo1 {public Demo1() {// TODO Auto-generated constructor stub}/** *反射：动态获取类(class)及类中成员，并对类中的成员运行 * *怎么获取到Class对象 * *动态获取Person.class对象 *获取方式有三种： *1：使用Object中的getClass()方法 *   需要先创建对象，所以的需要其所属的类实现存在  *:2：每个数据类型都有一个静态的属性class,通过该属性可以得到其所属的字节码文件对象 *    不需要创建对象了，但是需要那个类存在 * 3:Class.forName()只需要提供一个字符串，这个字符串的内容是类的名字 *  */public static void main(String[] args) throws ClassNotFoundException {//getClass1();//getClass2();getClass3();    }private static void getClass3() throws ClassNotFoundException {Class claz = Class.forName("com.qianfeng.reflect.Person");System.out.println(claz);}private static void getClass2() {Class claz1 = Person.class;Class claz2 = Person.class;System.out.println(claz1==claz2);}private static void getClass1() { Person p1 = new Person(); Class claz = p1.getClass();//Person.class   Person p2 = new Person(); Class claz2 = p2.getClass();//Person.class  System.out.println(claz==claz2); }}

package com.qianfeng.reflect;import java.lang.reflect.Constructor;import java.lang.reflect.InvocationTargetException;public class Demo2 {public Demo2() {// TODO Auto-generated constructor stub}/** * 动态获取类并创建对象  * @throws ClassNotFoundException  * @throws IllegalAccessException  * @throws InstantiationException  * @throws SecurityException  * @throws NoSuchMethodException  * @throws InvocationTargetException  * @throws IllegalArgumentException  */public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException, SecurityException, IllegalArgumentException, InvocationTargetException {         createObj1();         createObj2();}    //使用带参数的构造方法创建对象private static void createObj2() throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {//Person  p = new Person("lisi",23);Class claz = Class.forName("com.qianfeng.reflect.Person");Constructor cons = claz.getConstructor(String.class,int.class);Object obj = cons.newInstance("lili",23);System.out.println(obj);}private static void createObj1() throws ClassNotFoundException, InstantiationException, IllegalAccessException {//Person  p = new Person();Class claz = Class.forName("com.qianfeng.reflect.Person");//Person.classObject obj = claz.newInstance();//用的是默认的空参数的构造方法System.out.println(obj);}}

package com.qianfeng.reflect;import java.lang.reflect.Field;public class Demo3 {public Demo3() {// TODO Auto-generated constructor stub}/** * 动态创建对象并给属性赋值  * @throws ClassNotFoundException  * @throws SecurityException  * @throws NoSuchFieldException  * @throws IllegalAccessException  * @throws InstantiationException  */public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, SecurityException, InstantiationException, IllegalAccessException {        accessField1();}   //动态创建对象并给属性赋值 private static void accessField1() throws ClassNotFoundException, NoSuchFieldException, SecurityException, InstantiationException, IllegalAccessException {//Person p = new Person();//p.name = "";Class claz = Class.forName("com.qianfeng.reflect.Person");//Field field = claz.getField("name");//只能获取公共的成员属性Field field = claz.getDeclaredField("name");//只要是在类中的声明的就可以得到//创建一个Person类型的对象Object obj = claz.newInstance();//设置可以访问该属性---暴力访问field.setAccessible(true);field.set(obj, "zhangsan");System.out.println(obj);}}

package com.qianfeng.reflect;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;public class Demo4 {public Demo4() {// TODO Auto-generated constructor stub}/** * 动态执行类中的方法 * @throws ClassNotFoundException  * @throws SecurityException  * @throws NoSuchMethodException  * @throws InvocationTargetException  * @throws IllegalArgumentException  * @throws IllegalAccessException  * @throws InstantiationException  */public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {invokeMethod1();invokeMethod2();invokeMethod3();}    private static void invokeMethod3() throws ClassNotFoundException, NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {    Class claz = Class.forName("com.qianfeng.reflect.Person");        Method m = claz.getMethod("fun",null);        m.invoke(null,null);}private static void invokeMethod2() throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {    Class claz = Class.forName("com.qianfeng.reflect.Person");        Method m = claz.getMethod("method", String.class);        //创建对象    Object obj = claz.newInstance();        m.invoke(obj, "haha");}//执行无参数的方法private static void invokeMethod1() throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {//Person p = new Person();//p.show();Class claz = Class.forName("com.qianfeng.reflect.Person");//得到方法Method   m = claz.getMethod("show",null);//创建对象Object obj = claz.newInstance();m.invoke(obj, null);}}