java list属性排序 java list按照某个属性排序

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编程小天才 2023-07-16 11:33:11

文章标签 java list属性排序 java System List 文章分类 Java 后端开发

便于观察和理解，直接奉上代码，首先需要定义一个学生类，属性有name（姓名）、age（年龄）和score（分数）：

方法一：按照name（姓名）属性排序，要求创建的学生对象姓名为英文字符串（不可比较中文字符）。

定义学生类实现Comparable接口：

class Student implements Comparable<Student>{
	private String name;
	private int age;
	private double score;
	public Student(String name, int age, double score) {
		super();
		this.name = name;
		this.age = age;
		this.score = score;
	}
	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 getScore() {
		return score;
	}
	public void setScore(double score) {
		this.score = score;
	}
//按照英文字母组成的属性排序
	 @Override
	    public int compareTo(Student stu) {
	        return this.name.compareTo(stu.getName()); //升序  
	    }
}

main方法类：

package Java练习题1114;
import java.text.Collator;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

public class studentSort {
	public static void main(String[] args) {
	    //初始化学生类
		Student[] stu = {new Student("zhangsan", 20, 88),new Student("lisi", 22, 74),new Student("wangwu", 19, 83),new Student("zhaoliu", 16, 96),new Student("maqi", 25, 65)};
		//打印开始顺序
		System.out.println("开始顺序为：");
		List<Student> list = Arrays.asList(stu);
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
		//按照英文 姓名 排序
		Collections.sort(list);
        //打印排序后的顺序
		System.out.println("按照年龄排序后：");
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
	}
}

方法二：按照name（姓名）属性排序，要求创建的学生对象姓名为中文字符串（中文、英文都可比较）。

同上，定义学生类实现Comparable接口：

class Student implements Comparable<Student>{
	private String name;
	private int age;
	private double score;
	public Student(String name, int age, double score) {
		super();
		this.name = name;
		this.age = age;
		this.score = score;
	}
	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 getScore() {
		return score;
	}
	public void setScore(double score) {
		this.score = score;
	}
	//比较属性可以出现中文(例如 姓名 可以是中文)
	@Override
    public int compareTo(Student stu) {
		 Comparator<Object> com = Collator.getInstance(Locale.CHINA);
	     return ((Collator) com).compare(this.name,stu.getName());  //升序 
    }
}

main方法类：

package Java练习题1114;
import java.text.Collator;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

public class studentSort {
	public static void main(String[] args) {
	    //初始化学生类
		Student[] stu = {new Student("张三", 20, 88),new Student("李四", 22, 74),new Student("王五", 19, 83),new Student("赵六", 16, 96),new Student("马七", 25, 65)};
		//打印开始顺序
		System.out.println("开始顺序为：");
		List<Student> list = Arrays.asList(stu);
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
		//按照 中文 姓名 排序
		Collections.sort(list);
        //打印排序后的顺序
		System.out.println("按照年龄排序后：");
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
	}
}

方法三：按照age（年龄）属性排序，要求创建的学生对象的年龄（age）为 int 数据类型的。

同上，定义学生类实现Comparable接口：

class Student implements Comparable<Student>{
	private String name;
	private int age;
	private double score;
	public Student(String name, int age, double score) {
		super();
		this.name = name;
		this.age = age;
		this.score = score;
	}
	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 getScore() {
		return score;
	}
	public void setScore(double score) {
		this.score = score;
	}
	/*按照单个属性（int数据类型）排序
	 @Override
	    public int compareTo(Student stu) {
	        return this.age - stu.age; //升序 ，返回值为1 或-1 
	    }
}

main方法类：

package Java练习题1114;
import java.text.Collator;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

public class studentSort {
	public static void main(String[] args) {
	    //初始化学生类
		Student[] stu = {new Student("zhangsan", 20, 88),new Student("lisi", 22, 74),new Student("wangwu", 19, 83),new Student("zhaoliu", 16, 96),new Student("maqi", 25, 65)};
		//打印开始顺序
		System.out.println("开始顺序为：");
		List<Student> list = Arrays.asList(stu);
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
		//按照 （int 数据类型）年龄排序
		Collections.sort(list);
        //打印排序后的顺序
		System.out.println("按照年龄排序后：");
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
	}
}

方法四：按照score（分数）属性排序，要求创建的学生对象的分数（score）为double数据类型的。

同上，定义学生类实现Comparable接口：

class Student implements Comparable<Student>{
	private String name;
	private int age;
	private double score;
	public Student(String name, int age, double score) {
		super();
		this.name = name;
		this.age = age;
		this.score = score;
	}
	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 getScore() {
		return score;
	}
	public void setScore(double score) {
		this.score = score;
	}
	/*按照单个属性（double数据类型）排序
	   @Override
	    public int compareTo(Student stu) {
	        return  stu.getScore() - this.getScore() > 0 ? 1 : ((this.getScore() == stu.getScore()) ? 0 :-1);   //降序：返回值为1 或-1 升序改变变量位置即可
	    }
}

main方法类：

package Java练习题1114;
import java.text.Collator;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;

public class studentSort {
	public static void main(String[] args) {
	    //初始化学生类
		Student[] stu = {new Student("zhangsan", 20, 88),new Student("lisi", 22, 74),new Student("wangwu", 19, 83),new Student("zhaoliu", 16, 96),new Student("maqi", 25, 65)};
		//打印开始顺序
		System.out.println("开始顺序为：");
		List<Student> list = Arrays.asList(stu);
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
		//按照（double类型数据）排序
		Collections.sort(list);
        //打印排序后的顺序
		System.out.println("按照年龄排序后：");
		list.forEach((student) -> {
			System.out.println("姓名：" + student.getName() + "     年龄：" + student.getAge() + "   分数：" + student.getScore());
		});
	}
}

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