Java：包裝類，new初始化，去除復(fù)制后紅線，裝拆箱，解析轉(zhuǎn)換類型，人類抽象類，接口
1、定義4種包裝類型的變量，使用new關(guān)鍵字初始化這些變量。
package a;
public class fuxi {
public static void main(String[] args) {
Integer m1 = new Integer(5);
Boolean B1 = new Boolean(true);
Double D1 = new Double(52.0);
Byte Byte1 = new Byte("5");
Short Short1 = new Short("7");
Long Long1 = new Long("520");
Character Character1 = new Character('5');
Float Float1 = new Float(52.0);
System.out.print("Integer:" + m1 + " ,Boolean:" + B1 + ",Double:" + D1
+ ",Byte:" + Byte1 + ",Short:" + Short1 + ",Long:" + Long1
+ ",Character:" + Character1 + ",Float:" + Float1);
}
}
/*自己寫(xiě)和出的擴(kuò)展題(記錄自己的理解）：使用vlueOf()方法將轉(zhuǎn)換類型*/
package a;
public class fuxi {
public static void main(String[] args) {
Integer yuanlaideint = Integer.valueOf(100);
byte b = yuanlaideint.byteValue();
double dd = yuanlaideint.doubleValue();
System.out.println("原來(lái)的int類型 =" + yuanlaideint);
System.out.println("由原來(lái)的int類型變成的byte 類型=" + b);
System.out.println(" 由原來(lái)的int類型變成的double 類型" + dd);
Double yuanlaidedouble = Double.valueOf("123.45");
double d = yuanlaidedouble.doubleValue();
float f = yuanlaidedouble.floatValue();
int i = yuanlaidedouble.intValue();
long l = yuanlaidedouble.longValue();
System.out.println("原來(lái)的double類型=" + yuanlaidedouble);
System.out.println("由原來(lái)的double類型變成的double類型=" + d);
System.out.println("由原來(lái)的double類型變成的float類型 = " + f);
System.out.println("由原來(lái)的double類型變成的int類型? =" + i);
System.out.println("由原來(lái)的double類型變成的long類型 =" + l);
}
}
/*自己寫(xiě)和出的擴(kuò)展題(記錄自己的理解）：使用vlueOf()，方法*/
package a;
public class fuxi {
public static void main(String[] args) {
String yuanlaidezifuchuan = "1111111";
int radix = 2;/* 二進(jìn)制 */
// Creates an Integer object from the string從字符串創(chuàng)建一個(gè)整數(shù)對(duì)象
Integer intobject = Integer.valueOf(yuanlaidezifuchuan, radix);
// Extracts the int value from the string從字符串中提取int值
int intValue = Integer.parseInt(yuanlaidezifuchuan, 2);
System.out.println("原來(lái)的字符串 = " + yuanlaidezifuchuan);
System.out.println("由原來(lái)的字符串轉(zhuǎn)變的2進(jìn)制=" + intobject);
System.out.println(" 由原來(lái)的字符串解析的2進(jìn)制=" + intValue);
}
}
// 3、定義4種包裝數(shù)據(jù)類型的數(shù)組，每個(gè)數(shù)組的長(zhǎng)度都是3。
// 對(duì)每種數(shù)組進(jìn)行賦值，并打印。
package a;
public class fuxi {
public static void main(String[] args) {
Integer[] ms = new Integer[3];
Boolean[] B = new Boolean[3];
Double[] D = new Double[3];
Byte[] Byte = new Byte[3];
Short[] Short = new Short[3];
Long[] Long = new Long[3];
Character[] Character = new Character[3];
Float[] Float = new Float[3];
Integer m1 = new Integer(5);
Integer m2 = new Integer(2);
Integer m3 = new Integer(0);
Boolean B1 = new Boolean(true);
Boolean B2 = new Boolean(true);
Boolean B3 = new Boolean(true);
Double D1 = new Double(52.0);
Double D2 = new Double(52.0);
Double D3 = new Double(13.14);
Byte Byte1 = new Byte("5");
Byte Byte2 = new Byte("2");
Byte Byte3 = new Byte("0");
Short Short1 = new Short("7");
Short Short2 = new Short("7");
Short Short3 = new Short("5");
Long Long1 = new Long("520");
Long Long2 = new Long("13");
Long Long3 = new Long("14");
Character Character1 = new Character('5');
Character Character2 = new Character('2');
Character Character3 = new Character('0');
Float Float1 = new Float(52.0);
Float Float2 = new Float(52.0);
Float Float3 = new Float(13.14);
ms[0] = m1;
ms[1] = m2;
ms[2] = m3;
B[0] = B1;
B[1] = B2;
B[2] = B3;
D[0] = D1;
D[1] = D2;
D[2] = D3;
Byte[0] = Byte1;
Byte[1] = Byte2;
Byte[2] = Byte3;
Short[0] = Short1;
Short[1] = Short2;
Short[2] = Short3;
Long[0] = Long1;
Long[1] = Long2;
Long[2] = Long3;
Character[0] = Character1;
Character[1] = Character2;
Character[2] = Character3;
Float[0] = Float1;
Float[1] = Float2;
Float[2] = Float3;
for (int i = 0; i < ms.length; i++) {
System.out.print(ms[i] + "? ");
}
System.out.println();
for (int i = 0; i < ms.length; i++) {
System.out.print(B[i] + "? ");
}
System.out.println();
for (int i = 0; i < ms.length; i++) {
System.out.print(D[i] + "? ");
}
System.out.println();
for (int i = 0; i < ms.length; i++) {
System.out.print(Byte[i] + "? ");
}
System.out.println();
for (int i = 0; i < ms.length; i++) {
System.out.print(Short[i] + "? ");
}
System.out.println();
for (int i = 0; i < ms.length; i++) {
System.out.print(Character[i] + "? ");
}
System.out.println();
for (int i = 0; i < ms.length; i++) {
System.out.print(Float[i] + "? ");
}
}
}
// 2、對(duì)4種包裝類型使用valueOf方法和parseXxx方法
package a;
public class fuxi {
public static void main(String[] args) {
Integer yuanlaideInteger = 1;
String yuanlaidezifuchuan = "1111111";
// Boolean yuanlaideBoolean = null;
Double yuanlaideDouble = 1.1;
Byte yuanlaideByte = 1;
Short yuanlaideShort = 1;
Long yuanlaideLong = (long) 1;
Character yuanlaideCharacter = '1';
Float yuanlaideFloat = (float) 1;
int radix = 2;/* 二進(jìn)制 */
Integer intobject = Integer.valueOf(yuanlaidezifuchuan, radix);
int intValue = Integer.parseInt(yuanlaidezifuchuan, 2);
System.out.println("原來(lái)的String = " + yuanlaidezifuchuan);
System.out.println("由原來(lái)的String轉(zhuǎn)變的2進(jìn)制Integer=" + intobject);
System.out.println(" 由原來(lái)的String解析的2進(jìn)制int=" + intValue);
// Boolean yuanlaideBooleanv = Boolean.valueOf(yuanlaideBoolean);
//
// boolean yuanlaideBooleanp = Boolean.parseBoolean(yuanlaidezifuchuan);
// System.out.println("原來(lái)的Boolean? = " + yuanlaideBoolean);
// System.out.println("由原來(lái)的Boolean 轉(zhuǎn)變的Boolean=" + yuanlaideBooleanv);
// System.out.println(" 由原來(lái)的Boolean解析的boolean=" + yuanlaideBooleanp);
Integer yuanlaideDoublev = Integer.valueOf(16);
System.out.println("原來(lái)的Double? = " + yuanlaideDouble);
System.out.println("由原來(lái)的Double 轉(zhuǎn)變的16進(jìn)制Integer=" + yuanlaideDoublev);
Integer yuanlaideIntegerv = Integer.valueOf(16);
System.out.println("原來(lái)的Integer = " + yuanlaideInteger);
System.out.println("由原來(lái)的Integer轉(zhuǎn)變的16進(jìn)制Integer=" + yuanlaideIntegerv);
Integer yuanlaideBytev = Integer.valueOf(yuanlaidezifuchuan, 16);
int yuanlaideBytep = Integer.parseInt(yuanlaidezifuchuan, 2);
System.out.println("原來(lái)的Byte = " + yuanlaideByte);
System.out.println("由原來(lái)的Byte 轉(zhuǎn)變的16進(jìn)制Integer=" + yuanlaideBytev);
System.out.println(" 由原來(lái)的Byte解析的2進(jìn)制Integer=" + yuanlaideBytep);
Integer yuanlaideShortv = Integer.valueOf(7);
System.out.println("原來(lái)的Short? = " + yuanlaideShort);
System.out.println("由原來(lái)的Short 轉(zhuǎn)變的7進(jìn)制Integer=" + yuanlaideShortv);
Integer yuanlaideLongv = Integer.valueOf(yuanlaidezifuchuan, 9);
int yuanlaideLongp = Integer.parseInt(yuanlaidezifuchuan, 2);
System.out.println("原來(lái)的Long? = " + yuanlaideLong);
System.out.println("由原來(lái)的Long 轉(zhuǎn)變的9進(jìn)制Integer=" + yuanlaideLongv);
System.out.println(" 由原來(lái)的Long解析的2進(jìn)制Integer=" + yuanlaideLongp);
Integer yuanlaideCharacterv = Integer.valueOf(8);
System.out.println("原來(lái)的Character? = " + yuanlaideCharacter);
System.out
.println("由原來(lái)的Character 轉(zhuǎn)變的8進(jìn)制Integer=" + yuanlaideCharacterv);
Integer yuanlaideFloatv = Integer.valueOf(9);
System.out.println("原來(lái)的Float? = " + yuanlaideFloat);
System.out.println("由原來(lái)的Float轉(zhuǎn)變的9進(jìn)制Integer=" + yuanlaideFloatv);
}
}
聲明一個(gè)人類抽象類，人類都有吃飯和睡覺(jué)的功能，人類包含學(xué)生和老師，學(xué)生獨(dú)有功能上課,老師獨(dú)有功能講課
學(xué)生張三獨(dú)有的功能打籃球，學(xué)生李四獨(dú)有功能踢足球
老師A獨(dú)有功能看電視老師B獨(dú)有功能釣魚(yú)
老師和學(xué)生都8點(diǎn)上課(使用抽象類和接口做)
package a;
public class fuxi {
public static void main(String[] args) {
renlei A = new teacher("老師A");
renlei B = new teacher("老師B");
renlei Z = new student("張三");
renlei L = new student("李四");
renlei[] ms = new renlei[4];
ms[0] = A;
ms[1] = B;
ms[2] = Z;
ms[3] = L;
for (int i = 0; i < ms.length; i++) {
if (ms[i] instanceof teacher) {
if (i == 0) {
((teacher) ms[i]).jk();
((teacher) ms[i]).sj();
((teacher) ms[i]).kds();
} else if (i == 1) {
((teacher) ms[i]).jk();
((teacher) ms[i]).dy();
((teacher) ms[i]).sj();
}
}
else if (ms[i] instanceof student) {
if (i == 2) {
((student) ms[i]).sk();
((student) ms[i]).sj();
((student) ms[i]).dlq();
} else if (i == 3) {
((student) ms[i]).sk();
((student) ms[i]).sj();
((student) ms[i]).tzq();
}
}
}
/* 向上轉(zhuǎn)型，用上抽象類。向上轉(zhuǎn)型，用上接口 */
}
}
interface jiangke {
public abstract void bk();
void jk();
}
abstract class renlei {
int age;
String id;
String name;
public abstract void chifan();
public abstract void shuijiao();
}
interface shangke {
public abstract void sk();
}
class student extends renlei implements shangke {
public student(String name) {
this.name = name;
}
@Override
public void chifan() {
System.out.println(this.name + "吃飯");
}
public void dlq() {
System.out.println(this.name + "打籃球");
}
@Override
public void shuijiao() {
System.out.println(this.name + "睡覺(jué)");
}
public void sj() {
System.out.println(this.name + "8點(diǎn)上課");
}
@Override
public void sk() {
System.out.println(this.name + "在上課");
}
public void tzq() {
System.out.println(this.name + "踢足球");
}
}
class teacher extends renlei implements jiangke {
public teacher(String name) {
this.name = name;
}
@Override
public void bk() {
// TODO Auto-generated method stub
}
@Override
public void chifan() {
System.out.println(this.name + "在吃飯");
}
public void dy() {
System.out.println(this.name + "釣魚(yú)");
}
@Override
public void jk() {
System.out.println(this.name + "在講課");
}
public void kds() {
System.out.println(this.name + "看電視");
}
@Override
public void shuijiao() {
System.out.println(this.name + "睡覺(jué)");
}
public void sj() {
System.out.println(this.name + "8點(diǎn)上課");
}
}
