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测试clone

package cn.xx

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

/**
*


 * @Types   role : 测试clone

 * @Create  time : 2011-12-26 : 上午10:49:39
 * @ver     curr : 1.0
 *

*/
public class TestClone implements Serializable{

   private static final long serialVersionUID = -7340886443308126418L;

   /**
   *


     * @Methods role : 对象的Clone
     * 注: 要clone对象必须要实现Serializable接口,　不然抛NoSerializableException
     *

   * @param obj
   * @return
   * @throws IOException
   * @throws ClassNotFoundException
   * @Create time : 2011-12-23 : 下午5:26:57
   * @ver     curr : 1.0
   */
   @SuppressWarnings("unchecked")
   public static T invokeCopy(T obj) throws IOException, ClassNotFoundException{
       //T newObj = null;
       // write object to memory
       ByteArrayOutputStream bos = new ByteArrayOutputStream();
       ObjectOutputStream oos = new ObjectOutputStream(bos);
       oos.writeObject(obj);
       oos.flush();

       // read object come from memory
       ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
       ObjectInputStream ois = new ObjectInputStream(bis);
       //newObj = (T)ois.readObject();

       //bis.close();
       //oos.close();
       // return clone object
       return (T)ois.readObject();


   }

   /**
   *


     * @Methods role : 实现对象的clone
     * 两种方案(二选一实现都可以):
     * 1: 实现Cloneable接口,　深度clone自己重写clone()实现,此方法只实现浅度clone
     * 2: 实现Serializable接口
     * @param obj
     * @return
     * @throws NoSuchMethodException
     * @throws SecurityException
     * @throws IllegalAccessException
     * @throws IllegalArgumentException
     * @throws InvocationTargetException
     * @throws ClassNotFoundException
     * @throws IOException
     * @throws CloneNotSupportedException
     * @Create  time : 2011-12-26 : 上午10:31:37
     * @ver     curr : 1.0
     *

   */
   public static T clone(T obj) throws NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, ClassNotFoundException, IOException, CloneNotSupportedException{
       // is null
       if(null == obj) return null;

       // is instanceof Cloneable
       if(obj instanceof Cloneable){
           return invokeClone(obj);
       }
       // is instanceof Serializable
       else if(obj instanceof Serializable){
           return invokeCopy(obj);
       }

       // is not supported clone
       throw new java.lang.CloneNotSupportedException();
   }

   @SuppressWarnings("unchecked")
   public static T invokeClone(T obj) throws NoSuchMethodException,
           IllegalAccessException, InvocationTargetException {
       Class classObject = obj.getClass();
       Method method = classObject.getDeclaredMethod("clone");
       return (T)method.invoke(obj);
   }

   public static void main(String[] args) throws ClassNotFoundException, IOException {
       String x = "123";
       String v = invokeCopy(x);

       String[][] array = {{"1", "2"},{ "3", "2","2","3"},{"V","3"}}, array2;


       System.out.println(x);
       System.out.println(v);
       array2 = invokeCopy(array);
       System.out.println(Arrays.deepToString(array2));

       int[] a = {1,48,2}, b = {1, 20, 19};
       System.out.println("a --- hashCode: " + a.hashCode() + "---b: hashCode:" + b.hashCode());
       b = invokeCopy(a);
       System.out.println(b.hashCode());
       System.out.println(Arrays.toString(b));
       short age = 25;
       Person p = new TestClone(). new Person(1l, "andy", age), ps, pe;

       ps = invokeCopy(p);

       System.out.println(ps);

       try {
           //pe = clone(p);
           pe = invokeClone(p);
           System.out.println(pe);
       } catch (NoSuchMethodException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (SecurityException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalAccessException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalArgumentException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvocationTargetException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   class Person implements Serializable{//, Cloneable{
       private static final long serialVersionUID = 7605971168826706980L;
       private Long id;
       private String name;
       private short age;


       public Person() {
       }


       public Person(Long id, String name, short age) {
           super();
           this.id = id;
           this.name = name;
           this.age = age;
       }

       public Long getId() {
           return id;
       }
       public void setId(Long id) {
           this.id = id;
       }
       public String getName() {
           return name;
       }
       public void setName(String name) {
           this.name = name;
       }
       public short getAge() {
           return age;
       }
       public void setAge(short age) {
           this.age = age;
       }

       public String toString() {
           return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
       }

       /*protected Object clone() throws CloneNotSupportedException {
           // TODO Auto-generated method stub
           return super.clone();
       }*/

   }
}

为什么要关闭和io流

package cn.webmctv.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

public class TestInputStream {

   public static void main(String[] args) {
       /* 为什么要关闭和io流, 由于java底层是用c实现的，　所以当我们不停的调用new InputStream -> impl
       * 时候，　c打开的文件会一直没有关闭，而导致文件删除不了，别的程序访问不了的问题，和操作系统打开文件
       * 超过最大数异常。而下面new FileInputStream(new File("c:/q.txt"));这种方式没有关闭c打开的
       * 文件一直new 就会出现打开文件太多异常。
       short count = 0;
       InputStream inStream = null;
           try {
               for (int i = 0; i < Short.MAX_VALUE; i++) {
                   //inStream.
                   inStream = new FileInputStream(new File("/root/install.log"));
                   //count ++;
                   System.out.println("count: " + count++);
               }
               //p.load(inStream);
           } catch (FileNotFoundException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           } finally{
               if(inStream != null) try{ inStream.close(); } catch(IOException e){};
           }

       System.out.println(Short.MAX_VALUE);
       */
       short count = 0;
       InputStream inStream = null;
       for (int i = 0; i < Short.MAX_VALUE; i++) {
           try {
                   //inStream.
                   inStream = new FileInputStream(new File("/root/install.log"));
                   //count ++;
                   System.out.println("count: " + count++);

               //p.load(inStream);
           } catch (FileNotFoundException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           } finally{
               if(inStream != null) try{ inStream.close(); } catch(IOException e){};
           }
       }

       System.out.println(Short.MAX_VALUE);

   }
}

两个变量不通过第三个变量交换值

package cn.coder.y2010.m03.d27;

/**
* 两个变量不通过第三个变量交换值
*/
public class SwitchIntValue {

    public static void main(String[] args) {
    int i = 5,j = 3;
    i = i + j; // 5 + 3;
    j = i - j; // 8 - 3;
    i = i - j; // 8 - 5;
    System.out.println(i + " - : - " + j);
    }
}

MD5初解

1    public static String md5(String pwd) throws NoSuchAlgorithmException {
2
3    StringBuilder sb = new StringBuilder();
4    MessageDigest digest = MessageDigest.getInstance("md5");
5    byte[] b = digest.digest(pwd.getBytes());
6    // 与16进制进行与
7    // 16 59 1011001
8    // 59>>>4&0xf 101 | 59&0xf 1011001
9    // &1111 | &00001111
10    // 结果 101 | 00001001
11    // 16进制 5 9
12    for (byte s : b) {
13        // 左边的四位0101
14        //sb.append(Character.forDigit(
15        //    ((s >>> 4) & 0xf) > 4 ? (s >>> 4) & 0xf ^ 0xe
16        //        : (s >>> 4) & 0xf, 16));
17        sb.append(Character.forDigit((s >>> 4) & 0xf, 16));
18        // 右边的四位1001
19        sb.append(Character.forDigit(s & 0xf, 16));
20    }
21    // 所有MD5的生面0-f之间的字母与数字
22    return sb.toString().toUpperCase();
23    }

URL编码

摘要: 阅读全文

JAVA 序列化

package cn.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class TestSeralizable implements Serializable{

private static final long serialVersionUID = -2495488416590182981L;

    /**
     * 保存序列化的对像
     * @param path
     * @param o
     */
    public void writeObject(String path, Object o){
File file = new File(path);
if(file.exists()){
     file.delete();
}

FileOutputStream stream = null;
ObjectOutputStream outputStream = null;

try {
     stream = new FileOutputStream(file);
     outputStream = new ObjectOutputStream(stream);
     outputStream.writeObject(o);
} catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
} finally{
     try {
  stream.close();
  outputStream.close();
     } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
     } finally{
  stream = null;
  outputStream = null;
     }
}

    }

    /**
     * 读取序列化对像
     * @param
     * @param path
     * @return
     */
    @SuppressWarnings("unchecked")
    public T readObject(String path){
File file = new File(path);
if(!file.exists()){
     return null;
}
FileInputStream stream = null;
ObjectInputStream inputStream = null;

try {
     stream = new FileInputStream(file);
     inputStream = new ObjectInputStream(stream);

     return (T)inputStream.readObject();
} catch (FileNotFoundException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
} catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
} catch (ClassNotFoundException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
} finally{
     try {
  stream.close();
  inputStream.close();
     } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
     } finally{
  stream = null;
  inputStream = null;
     }
}

return null;
    }

    public static void main(String[] args) {
// --------------- 创建序列化实例   ----------------------//

TestSeralizable test = new TestSeralizable();
TestSeralizable.UserBean user = new TestSeralizable().new UserBean();
user.setName("wkw");
user.setAge(24);
user.setEmail("wkw11@163.com");
user.setPassword("123");

// --------------- 保存序列化实例   ----------------------//
test.writeObject("c:/qq.tmp", user);

// --------------- 读取序列化实例   ----------------------//
UserBean unSeralizableObject = test.readObject("c:/qq.tmp");
System.out.println(unSeralizableObject);
    }

    /**
     * 内部类
     * @author Administrator
     *
     */
    public class UserBean implements Serializable{

     private String name;
     private String password;
     private Integer age;
     private String email;



     /**
      *
      */
     public UserBean() {
  super();
  // TODO Auto-generated constructor stub
     }

     /**
      * @param name
      * @param password
      * @param age
      * @param email
      */
     public UserBean(String name, String password, Integer age, String email) {
  super();
  this.name = name;
  this.password = password;
  this.age = age;
  this.email = email;
     }

     public String getName() {
         return name;
     }

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

     public String getPassword() {
         return password;
     }

     public void setPassword(String password) {
         this.password = password;
     }

     public Integer getAge() {
         return age;
     }

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

     public String getEmail() {
         return email;
     }

     public void setEmail(String email) {
         this.email = email;
     }

private static final long serialVersionUID = 7645220056029053735L;

     @Override
     public String toString() {
  // TODO Auto-generated method stub
  return "[" + this.name + "," + this.password + "," + this.age + "," + this.email +"]";
     }

}
}