python通达信api接口,接口
行为标准,例如:USBpython通达信api接口,接口Java中为了限定某些类但是这些类都具有相同的行为特征例如JDBCJava中设计了很多python通达信api接口,接口,Connection,Statement,ResultSet
*如何去声明python通达信api接口,接口*【权限修饰符】interfacepython通达信api接口,接口名{
python通达信api接口,接口的成员列表}*使用者如何去使用python通达信api接口,接口
*python通达信api接口,接口的实现
【修饰符】class实现类extends父类implementspython通达信api接口,接口们{}python通达信api接口,接口的特点python通达信api接口,接口是标准,就是用来被实现的,那么要求实现类在实现python通达信api接口,接口时,必须实现/重写所有抽象方法,否则这个类就得是一个抽象类python通达信api接口,接口不能创建对象,但是python通达信api接口,接口类型的变量与实现类的对象构成多态一个类继承父类时,Java只支持单继承,但是一个类在实现python通达信api接口,接口时可以同时实现多个python通达信api接口,接口一个类如果同时继承父类,又实现python通达信api接口,接口,要求继承在前,实现在后在Java中python通达信api接口,接口可以继承python通达信api接口,接口【修饰符】interfance子python通达信api接口,接口extends父python通达信api接口,接口们{}
public class TestInterface {
public static void main(String[] args) {
//Flyable f = new Flyable(); python通达信api接口,接口不能创建对象
Flyable[] sky = new Flyable[3];
sky[0]=new Bird();
sky[1]=new Bird();
sky[2]=new Plane();
for(int i=0;ijavutiComparatorpython通达信api接口,接口:是泛型,还没有讲,换成Object抽象方法:intcompara(Objecto1,Objecto这个python通达信api接口,接口是代表Java中比较两个对像的大小。而且是一种定制的比较的标准。没有规定如何比较两个对象的大小如果你认为o1大于o就返回正整数,反之负整数,相等返回0
练习0按成绩比较大小
public class TestComparator {
public static void main(String[] args) {
Student t1 = new Student('V',25,80);
Student t2 = new Student('JK',23,90);
//比较t1和t2的大小
//对象无法直接比较大小if(t1>t2)
AgeComparator c = new AgeComparator();
System.out.print('t1和t2的年龄比较:');
if(c.compare(t1, t2)>0){
System.out.println('t1>t2');
}else if(c.compare(t1, t2)<0){
System.out.println('t1t2.getAge()){
return 1;
}else if(t1.getAge()t1和t2的年龄比较:t1>t2
练习02python通达信api接口,接口的练习声明一个员工类Employee,有属性:编号、姓名、年龄、薪资让Employee员工类实现javlanComparablepython通达信api接口,接口,重写抽象方法,按照编号从小到大排序在测试类中创建Employee[]数组,调用javutiArrays的sort方法进行排序,遍历结果声明SalaryComparator类,实现javutiComparatorpython通达信api接口,接口,重写抽象方法,按照薪资从高到低排序用SalaryComparator对象重新对Employee[]数组进行排序,遍历结果
public class Employee implements Comparable{
private int id;
private String name;
private int age;
private double salary;
public Employee(int id, String name, int age, double salary) {
super();
this.id = id;
this.name = name;
this.age = age;
this.salary = salary;
}
public Employee() {
super();
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
@Override
public String toString() {
return 'Employee [id=' + id + ', name=' + name + ', age=' + age
+ ', salary=' + salary + ']';
}
@Override
public int compareTo(Object o) {
return this.id-((Employee)o).id; //对int类型直接排序
}
}
import java.util.Comparator;
/*
* 4)声明SalaryComparator类,实现java.util.Comparatorpython通达信api接口,接口,
重写抽象方法,按照薪资从高到低排序
用SalaryComparator对象重新对Employee[]数组进行排序,遍历结果
*/
public class SalaryComparator implements Comparator {
@Override
public int compare(Object o1, Object o2) {
Employee e1=(Employee)o1;
Employee e2=(Employee)o2;
if(e1.getSalary()>e2.getSalary()){
return -1;
}else if(e1.getSalary()import java.util.Arrays;
//需求:编写一个Arrays的数组工具类,这个工具类,想要为任意的对象数组,进行升序排列
/*
* python通达信api接口,接口的练习2:
(1)声明一个员工类Employee,有属性:编号、姓名、年龄、薪资
(2)让Employee员工类实现java.lang.Comparablepython通达信api接口,接口,
重写抽象方法,按照编号从小到大排序
(3)在测试类中创建Employee[]数组,调用java.util.Arrays的sort方法进行排序,遍历结果
(4)声明SalaryComparator类,实现java.util.Comparatorpython通达信api接口,接口,
重写抽象方法,按照薪资从高到低排序
用SalaryComparator对象重新对Employee[]数组进行排序,遍历结果
*/
public class TestComparator2 {
public static void main(String[] args) {
Employee[] all = new Employee[3];
all[0]=new Employee(2,'Rm',26,2000);
all[1]=new Employee(3,'jk',23,3000);
all[2]=new Employee(1,'v',25,2500);
Arrays.sort(all);
for(int i=0;iEmployee[id=1,name=v,age=25,salary=2500.0]Employee[id=2,name=Rm,age=26,salary=2000.0]Employee[id=3,name=jk,age=23,salary=3000.0]
Employee[id=3,name=jk,age=23,salary=3000.0]Employee[id=1,name=v,age=25,salary=2500.0]Employee[id=2,name=Rm,age=26,salary=2000.0]
String类型的排序
public class TestString {
public static void main(String[] args) {
String s1='hello';
String s2='chai';
if(s1.compareTo(s2)>0){
System.out.println('s1>s2');
}else if(s1.compareTo(s2)<0){
System.out.println('s1s1>s2
将ID改为String类型是时
@Override
public int compareTo(Object o) {
Employee other = (Employee) o;
return id.compareTo(other.id); //对int类型直接排序
}
匿名内部类匿名内部类
语法格式:new父类名{类的成员列表}或new父python通达信api接口,接口名{类的成员列表}特殊:声明匿名内部类与创建它的对象是一起完成的。即匿名内部类只有唯一的对象
public class TestAnonymousInner {
@SuppressWarnings('unchecked')
public static void main(String[] args) {
//需求:要声明一个Object的子类,匿名子类
//并在子类中声明一个方法public void test(){}打印“hello匿名内部类”
//下面这段代码,声明了匿名内部类,也创建了它的对象,但是没哟有说这个对象干什么,编译不通过
/*new Object(){
public void test(){
System.out.println('hello匿名内部类');
}
}*/
//我们可以把这个对象赋值给一个变量
//多态引用(是Object子类的对象)
Object obj=new Object(){
public void test(){
System.out.println('hello匿名内部类');
}
};
/*Comparator c=new Comparator(){
@Override
public int compare(Object o1, Object o2) {
Circle c1=(Circle)o1;
Circle c2=(Circle)o2;
if(c1.getRadius()>c2.getRadius()){
return 1;
}else if(c1.getRadius()c2.getRadius()){
return 1;
}else if(c1.getRadius()c2.getRadius()){
return 1;
}else if(c1.getRadius()练习01匿名内部类练习1声明一个抽象类Father,包含抽象方法:publicabstractvoidmethod();用匿名内部类继承Father,并重写抽象方法,打印“hello孩子'并调用子类对象的method方法
public class lianxi03 {
public static void main(String[] args) {
new Father(){
@Override
public void method() {
System.out.println('hello孩子');
}
}.method();//并调用子类对象的method方法
}
}
abstract class Father{
public abstract void method();
}
hello孩子
匿名内部类练习2声明一个员工类Employee,有属性:编号、姓名、薪资在测试类中创建Employee数组分别调用Arrays.sort(数组,Comparator),用匿名内部类实现按照编号升序排列分别调用Arrays.sort(数组,Comparator),用匿名内部类实现按照薪资升序排列
package lianxi04;
//(1)声明一个员工类Employee,有属性:编号、姓名、薪资
public class Employee {
private int id;
private String name;
private int salary;
public Employee(int id, String name, int salary) {
super();
this.id = id;
this.name = name;
this.salary = salary;
}
public Employee() {
super();
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
@Override
public String toString() {
return 'Employee [id=' + id + ', name=' + name + ', salary=' + salary
+ ']';
}
}
package lianxi04;
import java.util.Arrays;
import java.util.Comparator;
/*
* 2、匿名内部类练习2
(1)声明一个员工类Employee,有属性:编号、姓名、薪资
(2)在测试类中创建Employee数组
(3)分别调用Arrays.sort(数组,Comparator),用匿名内部类实现按照编号升序排列
(4)分别调用Arrays.sort(数组,Comparator),用匿名内部类实现按照薪资升序排列
*/
public class TestEmployee {
@SuppressWarnings('unchecked')
public static void main(String[] args) {
Employee[] all=new Employee[3];
all[0]=new Employee(2,'V',2000);
all[1]=new Employee(3,'jk',1800);
all[2]=new Employee(1,'suga',3999);
Arrays.sort(all, new Comparator(){
@Override
public int compare(Object o1, Object o2) {
Employee e1=(Employee)o1;
Employee e2=(Employee)o2;
if(e1.getId()>e2.getId()){
return 1;
}else if(e1.getId()e2.getSalary()){
return 1;
}else if(e1.getSalary()Employee[id=1,name=suga,salary=3999]Employee[id=2,name=V,salary=2000]Employee[id=3,name=jk,salary=1800]
Employee[id=3,name=jk,salary=1800]Employee[id=2,name=V,salary=2000]Employee[id=1,name=suga,salary=3999]
或者:将if(egetId()>egetId()){return1;}elseif(egetId()
文章为作者独立观点,不代表 股票程序化软件自动交易接口观点