no message

lessonOne/out/production/lessonOne/com/company/test.txt

+Java 第一课
+ 全心全意为门店服务
+全心全意为门店服务
+全心全意为门店服务
+全心全意为门店服务全心全意为门店服务学习
+学习java 第一课
\ No newline at end of file

lessonOne/src/com/company/Main.java

+package com.company;
+
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static void main(String[] args) {
+
+        System.out.println("Java Lesson1");
+
+       // MapPractice();
+        //SetPractice();
+        //ArrayPractice();
+        //LinkdListPractice();
+        //IOReadPractice();
+        //IOWritePractice();
+        //FileReaderPractice();
+        //FileWriterPractice();
+        ThreadPractice();
+    }
+
+    /* HashMap 使用举例*/
+    public static void MapPractice()
+    {
+        //集合HashMap
+        Map<String,Object> hmCollect = new HashMap();
+        hmCollect.put("Age",18);  //插入数据
+        hmCollect.put("Name","test");
+        //获取数据
+        String name=hmCollect.get("Name").toString();
+
+        System.out.println("姓名："+name);
+
+        //更新集合
+        hmCollect.replace("Name","Java");
+
+        name=hmCollect.get("Name").toString();
+
+        System.out.println("姓名："+name);
+
+        //删除集合内数据
+        hmCollect.remove("Age");
+
+        //循环输出
+        hmCollect.forEach((k,v)->{
+            System.out.println("key："+k+"    value："+v);
+        });
+
+        System.out.println("****** for循环输出 ****** ");
+        for(Map.Entry<String,Object> entry:hmCollect.entrySet()) {
+            System.out.println("item：" + entry.getKey() + " " + entry.getValue());
+        }
+    }
+
+    public static void SetPractice() {
+        Set hs = new HashSet();
+
+        String str = "freemud";
+        hs.add(str);
+        hs.add("shop");
+
+        if(hs.contains("freemud"))
+        {
+            System.out.println("已经存在");
+        }
+
+        Iterator it=hs.iterator();
+        while(it.hasNext())
+        {
+            System.out.println(it.next());
+        }
+    }
+
+    public static void ArrayPractice() {
+        ArrayList arrLis = new ArrayList();
+        for (int i = 0; i < 10; i++) {
+            arrLis.add(i);
+        }
+
+        ArrayList<People> arrliss = new ArrayList<>();
+        arrliss.add(new People("freemud", 18));
+        arrliss.add(new People("shop",19));
+
+        Iterator it=arrliss.iterator();
+        while(it.hasNext())
+        {
+            People peo=(People)it.next();
+            System.out.println(peo.name);
+        }
+    }
+
+    public static void LinkdListPractice(){
+        LinkedList list = new LinkedList();
+        //list.add()
+        LinkedList<String> lis=new LinkedList<String>();
+        lis.add("123");
+        lis.add("freemud");
+
+        Iterator it= lis.iterator();
+
+        while(it.hasNext())
+        {
+            System.out.println(it.next());
+        }
+    }
+
+    //字节流读取
+    public static void IOReadPractice()
+    {
+        FileInputStream fos=null;
+        try
+        {
+          fos = new FileInputStream("D:\\Private\\SpringBootDemo-master\\SpringBootDemo-master\\lessonOne\\out\\production\\lessonOne\\com\\company\\test.txt");
+          byte bytes[]=new byte[1024];
+          int n=0;
+          while((n=fos.read(bytes))!= -1){
+              String str = new String(bytes,0,n);
+              System.out.print(str);
+          }
+        }
+        catch(Exception ex)
+        {
+            System.out.println("读取文件出错："+ex.getMessage());
+        }
+        finally
+        {
+            try
+            {
+                fos.close();
+            }
+            catch (Exception ex)
+            {
+
+            }
+        }
+    }
+
+    //字节流写入
+    public static void IOWritePractice()
+    {
+        FileOutputStream fos=null;
+        try
+        {
+            fos = new FileOutputStream("D:\\Private\\SpringBootDemo-master\\SpringBootDemo-master\\lessonOne\\out\\production\\lessonOne\\com\\company\\test.txt",true);
+            String str ="\r\n全心全意为门店服务";
+            byte bytes[] =str.getBytes();
+            fos.write(bytes);
+        }
+        catch(Exception ex)
+        {
+            System.out.println("写入出错："+ex.getMessage());
+        }
+        finally {
+           try
+           {
+               fos.close();
+           }
+           catch (Exception ex)
+           {
+
+           }
+        }
+    }
+
+    //字符流读取
+    public static void FileReaderPractice()
+    {
+        FileReader fr=null;
+        try
+        {
+            fr = new FileReader("D:\\Private\\SpringBootDemo-master\\SpringBootDemo-master\\lessonOne\\out\\production\\lessonOne\\com\\company\\test.txt");
+
+            char chars[] = new char[1024];
+            int n=0;
+            while((n=fr.read(chars))!= -1)
+            {
+                System.out.println(chars);
+            }
+        }
+        catch (Exception ex)
+        {
+            System.out.println("读取出错："+ex.getMessage());
+        }
+        finally {
+            try
+            {
+                fr.close();
+            }
+            catch (Exception ex)
+            {
+
+            }
+        }
+    }
+
+    //字符流写入
+    public static void FileWriterPractice()
+    {
+        FileWriter fw=null;
+        try
+        {
+            fw=new FileWriter("D:\\Private\\SpringBootDemo-master\\SpringBootDemo-master\\lessonOne\\out\\production\\lessonOne\\com\\company\\test.txt",true);
+            fw.write("\r\n学习java 第一课");
+
+        }
+        catch (Exception ex)
+        {
+
+        }
+        finally {
+            try {
+                fw.close();
+            }
+            catch (Exception ex)
+            {
+
+            }
+        }
+    }
+
+    public static void ThreadPractice()
+    {
+        ThreadTest thread1=new ThreadTest("开发");
+        thread1.start();
+
+        ThreadTest thread2=new ThreadTest("测试");
+        thread2.start();
+
+    }
+}
+

lessonOne/src/com/company/People.java

+package com.company;
+
+public class People {
+    public People(String name,int age)
+    {
+        this.name=name;
+        this.age=age;
+    }
+
+    public String name;
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int age;
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public int getAge() {
+        return age;
+    }
+}

lessonOne/src/com/company/ThreadTest.java

+package com.company;
+
+public class ThreadTest extends Thread{
+
+    public String workName;
+
+    public ThreadTest(String _workName)
+    {
+        this.workName=_workName;
+    }
+
+    @Override
+    public void run()
+    {
+        for(int i=0;i<6;i++)
+        {
+            System.out.println( "第"+i+"份工作："+this.workName);
+            try
+            {
+                Thread.sleep(1000);
+            }
+            catch (InterruptedException ex)
+            {
+                ex.printStackTrace();
+            }
+        }
+    }
+}

lessonOne/src/com/company/test.txt

+测试java
\ No newline at end of file