Java泛型使用之实现一个能够对字符、整型、浮点型、字节型、对象进行大小比较的方法

定义一个泛型类，定义泛型T，存储咱们的最大值最小值，重载构造函数，存储最大最小值，重写toString方法；

1package person.xsc.practice;
2
3public class Num<T> {
4	//定义最大最小值
5	public T max;
6	public T min;
7	public Num() {
8	}
9	//构造函数(有参)
10	public Num(T max, T min) {
11		this.max = max;
12		this.min = min;
13	}
14	public T getMax() {
15		return max;
16	}
17	public void setMax(T max) {
18		this.max = max;
19	}
20	public T getMin() {
21		return min;
22	}
23	public void setMin(T min) {
24		this.min = min;
25	}
26	@Override
27	public String toString() {
28		return "Num [max=" + max + ", min=" + min + "]";
29	}
30}
31

定义一个泛型方法比较最大最小值，传入我们的泛型数组

1package person.xsc.practice;
2
3public class GeneralCompareMethod {
4	public <T extends Comparable<T>> Num<T> getMaxMin(T[]num){
5		T max = num[0];
6		T min = num[0];
7		for (int i = 0; i < num.length; i++) {
8			if(max.compareTo(num[i])<0) {
9				max=num[i];
10			}
11			if(min.compareTo(num[i])>0) {
12				min=num[i];
13			}
14		}
15		return new Num<T>(max,min);
16	}
17}
18

定义一个studentII类，用于对象数组比较，实现 Comparable接口，并重写compareTo方法。

1package person.xsc.practice;
2
3public class StudentII implements Comparable{
4	private int number=0; //学号
5	private String name=""; //学生姓名
6	private String gender=""; //性别
7	public StudentII() {
8		
9	}
10	public StudentII(int number, String name, String gender) {
11		this.number = number;
12		this.name = name;
13		this.gender = gender;
14	}
15
16	public int getNumber() {
17		return number;
18	}
19
20	public void setNumber(int number) {
21		this.number = number;
22	}
23
24	public String getName() {
25		return name;
26	}
27
28	public void setName(String name) {
29		this.name = name;
30	}
31
32	public String getGender() {
33		return gender;
34	}
35
36	public void setGender(String gender) {
37		this.gender = gender;
38	}
39	
40	@Override
41	public String toString() {
42		return "StudentII [number=" + number + ", name=" + name + ", gender=" + gender + "]";
43	}
44
45	@Override
46	public int compareTo(Object o) {
47		// TODO Auto-generated method stub
48		StudentII student=(StudentII)o;
49		if(this.number==student.number){
50			return 0; //如果学号相同，那么两者就是相等的
51		}else if(this.number>student.getNumber()){
52			return 1; //如果这个学生的学号大于传入学生的学号
53		}else{
54			return -1; //如果这个学生的学号小于传入学生的学号
55		}
56	}
57
58}
59

定义测试类，数组实例化，调用比较大小方法。

1package person.xsc.practice;
2public class NumTest {
3	public static void main(String[] args) {
4		// TODO Auto-generated method stub
5		GeneralCompareMethod gcm=new GeneralCompareMethod();
6		System.out.println("=======整型数组比较=======");
7		Integer[]integerArray= {1,8,34,13,56};
8		System.out.println(gcm.getMaxMin(integerArray));
9		System.out.println("=======字符型数组比较=======");
10		Character[] charArray = { 'H', 'E', 'L', 'L', 'O' };
11		System.out.println(gcm.getMaxMin(charArray));
12		System.out.println("=======双精度型数组比较=======");
13		Double[] doubleArray = { 1.1, 2.2, 3.3, 4.4 };
14		System.out.println(gcm.getMaxMin(doubleArray));
15		System.out.println("=======StudentII对象数组比较=======");
16		StudentII[] stuArray= {new StudentII(1,"张三","男"),new StudentII(5,"李四","男"),new StudentII(2,"夏六","女")};
17		System.out.println(gcm.getMaxMin(stuArray));
18		System.out.println("=======字节型数组比较=======");
19		Byte[] byteArray = {'a','b','c','d'};
20		System.out.println(gcm.getMaxMin(byteArray));
21	}
22}
23

1=======整型数组比较=======
2Num [max=56, min=1]
3=======字符型数组比较=======
4Num [max=O, min=E]
5=======双精度型数组比较=======
6Num [max=4.4, min=1.1]
7=======StudentII对象数组比较=======
8Num [max=StudentII [number=5, name=李四, gender=男], min=StudentII [number=1, name=张三, gender=男]]
9=======字节型数组比较=======
10Num [max=100, min=97]
11