java list filter_Java8使用stream().filter()过滤List对象（查找符合条件的对象集合）

写在前面

使用Java8或更高版本，使用stream().filter()来过滤一个List对象，查找符合条件的对象集合。

List对象类

public class StudentInfo {

private String name;

private String gender;

private int age;

private int height;

public StudentInfo setName(String mName) {

name = mName;

return this;

}

public StudentInfo setGender(String mGender) {

gender = mGender;

return this;

}

public StudentInfo setAge(int mAge) {

age = mAge;

return this;

}

public StudentInfo setHeight(int mHeight) {

height = mHeight;

return this;

}

public String getName() {

return name;

}

public int getAge() {

return age;

}

public String getGender() {

return gender;

}

public int getHeight() {

return height;

}

@Override

public String toString() {

return "StudentInfo{" +

"name='" + name + '\'' +

", gender='" + gender + '\'' +

", age=" + age +

", height=" + height +

'}';

}

如上就是List对象类了。这里稍微的使用了一点链式编程。

测试数据

public static void main(String[] args) {

List lsStudentData = new ArrayList<>();

//数据添加

for (int i = 0; i < 30; i++) {

StudentInfo student = new StudentInfo();

student.setName("GT Name")

.setAge(i)

.setGender(i % 2 != 0 ? "Male" : "Female")

.setHeight(180);

lsStudentData.add(student);

}

//循环遍历数据

for (StudentInfo studentItem : lsStudentData) {

System.out.println(studentItem.toString());

}

使用filter()过滤List

过滤要求，我们需要寻找年龄大于等于15的年轻人。

List lsYoungStudent = lsStudentData.stream().filter(a -> a.getAge() >= 15).collect(Collectors.toList());

for (StudentInfo studentItem : lsYoungStudent) {

System.out.println(studentItem.toString());

}

进行年龄大于等于15的过滤操作。

StudentInfo{name='GT Name', gender='Female', age=0, height=180}

StudentInfo{name='GT Name', gender='Male', age=1, height=180}

StudentInfo{name='GT Name', gender='Female', age=2, height=180}

StudentInfo{name='GT Name', gender='Male', age=3, height=180}

StudentInfo{name='GT Name', gender='Female', age=4, height=180}

StudentInfo{name='GT Name', gender='Male', age=5, height=180}

StudentInfo{name='GT Name', gender='Female', age=6, height=180}

StudentInfo{name='GT Name', gender='Male', age=7, height=180}

StudentInfo{name='GT Name', gender='Female', age=8, height=180}

StudentInfo{name='GT Name', gender='Male', age=9, height=180}

StudentInfo{name='GT Name', gender='Female', age=10, height=180}

StudentInfo{name='GT Name', gender='Male', age=11, height=180}

StudentInfo{name='GT Name', gender='Female', age=12, height=180}

StudentInfo{name='GT Name', gender='Male', age=13, height=180}

StudentInfo{name='GT Name', gender='Female', age=14, height=180}

StudentInfo{name='GT Name', gender='Male', age=15, height=180}

StudentInfo{name='GT Name', gender='Female', age=16, height=180}

StudentInfo{name='GT Name', gender='Male', age=17, height=180}

StudentInfo{name='GT Name', gender='Female', age=18, height=180}

StudentInfo{name='GT Name', gender='Male', age=19, height=180}

StudentInfo{name='GT Name', gender='Female', age=20, height=180}

StudentInfo{name='GT Name', gender='Male', age=21, height=180}

StudentInfo{name='GT Name', gender='Female', age=22, height=180}

StudentInfo{name='GT Name', gender='Male', age=23, height=180}

StudentInfo{name='GT Name', gender='Female', age=24, height=180}

StudentInfo{name='GT Name', gender='Male', age=25, height=180}

StudentInfo{name='GT Name', gender='Female', age=26, height=180}

StudentInfo{name='GT Name', gender='Male', age=27, height=180}

StudentInfo{name='GT Name', gender='Female', age=28, height=180}

StudentInfo{name='GT Name', gender='Male', age=29, height=180}

过滤后数据+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++