collections集合操作排序,Java8 stream集合操作

/**
*
*/
package com.wen;

import java.math.BigDecimal;

/**
* @author wencun
* @date 2018年2月22日 上午9:49:37
* @version 1.0
* @since JDK 1.8
*/
public class Staff {
private String name;
private int age;
private BigDecimal salary;

/**
* @return the name
*/
public String getName() {
return name;
}
/**
* @param name the name to set
*/
public void setName(String name) {
this.name = name;
}
/**
* @return the age
*/
public int getAge() {
return age;
}
/**
* @param age the age to set
*/
public void setAge(int age) {
this.age = age;
}
/**
* @return the salary
*/
public BigDecimal getSalary() {
return salary;
}
/**
* @param salary the salary to set
*/
public void setSalary(BigDecimal salary) {
this.salary = salary;
}
/**
* @param name
* @param age
* @param salary
*/
public Staff(String name, int age, BigDecimal salary) {
super();
this.name = name;
this.age = age;
this.salary = salary;
}
/* (non-Javadoc)
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return "Staff [name=" + name + ", age=" + age + ", salary=" + salary + "]";
}

}

package com.wen;

import java.math.BigDecimal;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
/**
* @author wencun
* @date 2018年2月22日 上午9:48:01
* @version 1.0
* @since JDK 1.8
*/

import org.junit.Test;
public class TestJava8 {

@Test
public void java8() throws Exception {
List<Staff> asList = Arrays.asList(new Staff("小明", 18, new BigDecimal(2000)),
new Staff("小明1", 33, new BigDecimal(22020)),
new Staff("小明2", 44, new BigDecimal(2800)),
new Staff("小明3", 23, new BigDecimal(2700)),
new Staff("小明4", 21, new BigDecimal(2600)),
new Staff("小明5", 10, new BigDecimal(2000)),
new Staff("小明6", 56, new BigDecimal(21000)),
new Staff("小明7", 49, new BigDecimal(12000)));

List<Integer> list=Arrays.asList(3,41,23,65,12,77,33, 1,4);
Collections.sort(list);
System.out.println("顺序"+list);
Collections.reverse(list);
System.out.println("倒序"+list);
Collections.shuffle(list);
System.out.println("混序"+list);

List<Integer> collect = asList.stream().map(e->e.getAge()).collect(Collectors.toList());
System.out.println("年龄集合"+collect);

List<BigDecimal> collect2 = asList.stream().map(Staff::getSalary).collect(Collectors.toList());
System.err.println("工资集合"+collect2);

asList.sort(new Comparator<Staff>() {

@Override
public int compare(Staff o1, Staff o2) {

return o1.getAge()-o2.getAge();
}
});
System.out.println("对象集合按年龄排序"+asList);
Collections.sort(collect);
System.out.println("年龄排序"+collect);

}

}

顺序[1, 3, 4, 12, 23, 33, 41, 65, 77]
倒序[77, 65, 41, 33, 23, 12, 4, 3, 1]
混序[65, 77, 1, 3, 33, 23, 12, 4, 41]
年龄集合[18, 33, 44, 23, 21, 10, 56, 49]
工资集合[20
4000
00, 22020, 2800, 2700, 2600, 2000, 21000, 12000]
对象集合按年龄排序[Staff [name=小明5, age=10, salary=2000], Staff [name=小明, age=18, salary=2000], Staff [name=小明4, age=21, salary=2600], Staff [name=小明3, age=23, salary=2700], Staff [name=小明1, age=33, salary=22020], Staff [name=小明2, age=44, salary=2800], Staff [name=小明7, age=49, salary=12000], Staff [name=小明6, age=56, salary=21000]]
年龄排序[10, 18, 21, 23, 33, 44, 49, 56]