开发笔记:编写高质量代码:改善Java程序的151个建议(第3章:类对象及方法___建议41~46)

public interface Father {
public int strong();
}
interface Mother {
public int kind();
}

class FatherImpl implements Father {
// 父亲的强壮指数为8
@Override
public int strong() {
return 8;
}
}
class MotherImpl implements Mother {
// 母亲的温柔指数为8
@Override
public int kind() {
return 8;
}
}

class Son extends FatherImpl implements Mother {
@Override
public int strong() {
// 儿子比父亲强壮
return super.strong() + 1;
}
@Override
public int kind() {
return new MotherSpecial().kind();
}
private class MotherSpecial extends MotherImpl {
@Override
public int kind() {
// 儿子的温柔指数降低了
return super.kind() - 1;
}
}
}

class Daughter extends MotherImpl implements Father {
@Override
public int strong() {
return new FatherImpl() {
@Override
public int strong() {
//女儿的强壮指数降低了
return super.strong() - 2;
}
}.strong();
}
}

public final class Math {
/**
* Don‘t let anyone instantiate this class.
*/
private Math() {}
}

class UtilsClazz{
public UtilsClazz(){
throw new Error("Don‘t instantiate "+getClass());
}
}

1 public class Person implements Cloneable {
2 public static void main(String[] args) {
3 // 定义父亲
4 Person f = new Person("父亲");
5 // 定义大儿子
6 Person s1 = new Person("大儿子", f);
7 // 小儿子的信息时通过大儿子拷贝过来的
8 Person s2 = s1.clone();
9 s2.setName("小儿子");
10 System.out.println(s1.getName() + " 的父亲是 " + s1.getFather().getName());
11 System.out.println(s2.getName() + " 的父亲是 " + s2.getFather().getName());
12 }
13 // 姓名
14 private String name;
15 // 父亲
16 private Person father;
17
18 public Person(String _name) {
19 name = _name;
20 }
21
22 public Person(String _name, Person _parent) {
23 name = _name;
24 father = _parent;
25 }
26
27 @Override
28 public Person clone() {
29 Person p = null;
30 try {
31 p = (Person) super.clone();
32 } catch (CloneNotSupportedException e) {
33 e.printStackTrace();
34 }
35 return p;
36
37 }
38
39 /*setter和getter方法略*/
40 }

public static void main(String[] args) {
// 定义父亲
Person f = new Person("父亲");
// 定义大儿子
Person s1 = new Person("大儿子", f);
// 小儿子的信息时通过大儿子拷贝过来的
Person s2 = s1.clone();
s2.setName("小儿子");
//认干爹
s1.getFather().setName("干爹");
System.out.println(s1.getName() + " 的父亲是 " + s1.getFather().getName());
System.out.println(s2.getName() + " 的父亲是 " + s2.getFather().getName());
}

public Person clone() {
Person p = null;
try {
p = (Person) super.clone();
p.setFather(new Person(p.getFather().getName()));
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
return p;
}

1 import java.io.ByteArrayInputStream;
2 import java.io.ByteArrayOutputStream;
3 import java.io.IOException;
4 import java.io.ObjectInputStream;
5 import java.io.ObjectOutputStream;
6 import java.io.Serializable;
7
8 public final class CloneUtils {
9 private CloneUtils() {
10 throw new Error(CloneUtils.class + " cannot instance ");
11 }
12
13 // 拷贝一个对象
14 public static extends Serializable> T clone(T obj) {
15 // 拷贝产生的对象
16 T clOneObj= null;
17 try {
18 // 读取对象字节数据
19 ByteArrayOutputStream baos = new ByteArrayOutputStream();
20 ObjectOutputStream oos = new ObjectOutputStream(baos);
21 oos.writeObject(cloneObj);
22 oos.close();
23 // 分配内存空间，写入原始对象，生成新对象
24 ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
25 ObjectInputStream ois = new ObjectInputStream(bais);
26 // 返回新对象， 并做类型转换
27 clOneObj= (T) ois.readObject();
28 ois.close();
29 } catch (ClassNotFoundException e) {
30 e.printStackTrace();
31 } catch (IOException e) {
32 e.printStackTrace();
33 }
34 return cloneObj;
35
36 }
37
38 }

public class Person implements Serializable{
private static final long serialVersiOnUID= 4989174799049521302L;
/*删除掉clone方法，其它代码保持不变*/
}

public class Person {
private String name;
public Person(String _name) {
name = _name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}

@Override
public boolean equals(Object obj) {
if(obj instanceof Person){
Person p = (Person) obj;
return name.equalsIgnoreCase(p.getName().trim());
}
return false;
}
}

public static void main(String[] args) {
Person p1= new Person("张三");
Person p2= new Person("张三 ");
List list= new ArrayList();
list.add(p1);
list.add(p2);
System.out.println("列表中是否包含张三："+list.contains(p1));
System.out.println("列表中是否包含张三："+list.contains(p2));
}

"张三 ".equalsIgnoreCase("张三");

public static void main(String[] args) {
Person p1= new Person("张三");
Person p2= new Person(null);
　　/*其它部分没有任何修改，不再赘述*/
}