Public class Student {
Private int number;
private String name;
Private String clazz;
Private int score;
Public Student (int number, a String name, String clazz, int score) {
This. Number=number;
this.name=name;
Enclosing clazz=clazz;
this.score=score;
}
//omit getter/setter methods
}
Write method in the following class, according to the demand, finish to the operation of the STUDENTS set
Public class StreamTest {
Private static final List
Private static final String CLAZZ1=class 1, "software";
Private static final String CLAZZ2="software 2 class";
Private static List
Student s1=new Student (2018008, "Yang", CLAZZ2, 66);
Student s2=new Student (2018005, "vlon CLAZZ1, 92);
Student s3=new Student (2018007, "li Ming", CLAZZ2, 42);
Student s4=new Student (2018006, "zhao yong," CLAZZ2, 56);
Student s5=new Student (2018002, "wang lei" CLAZZ1, 81);
Student s6=new Student (2018010, "NiuNa CLAZZ1, 78);
List
Students. The add (s1); Students. The add (s2); Students. The add (s3);
Students. The add (s4); Students. The add (s5); Students. The add (s6);
Return students;
}
Public static void main (String [] args) {
//call the method test
}
//implementation method
}
Description:
Requirements described in the specified X, refers to the method of parameter
All methods have a return value, try to return statements directly programming, based on the stream flow required results returned directly
If return to the collection, use the List collection type
Try to use shorthand
Pay attention to the filter code format
Method 1, get scores less than or equal to the specified band, all the students
Answer:
Method 2, access to the specified class, scores less than or equal to the specified band, all the students
Answer:
Methods 3, access to the specified class, scores less than or equal to the specified band, all the names of the students, pay attention to the return type
Answer:
Methods 4, according to the result from low to high order, return all student
Answer:
Methods 5, access to the specified class, scores less than or equal to the specified band, scores from high to low order, all the students
Answer:
Methods 6, access to the specified class, scores less than or equal to the specified band, scores from high to low sorting, all of the student's student id, note that the return type
Answer:
Methods 7, access to the specified class, scores less than or equal to the specified band, all the students
Student id as the key to the student, the student score for the value, the Map groups, return
Answer:
CodePudding user response:
Is not operating API, this to yourselfCodePudding user response:
Public static void main (String [] args) {
//method 1, get scores less than or equal to the specified band, all the students
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
ListScoredayu=STUDENTS. Stream (). The filter (student - & gt; Student. GetScore () & gt; 75). Collect (Collectors. ToList ());
Scoredayu. Stream (). The forEach (student - & gt; System. The out. Println (student));
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
//method 2, access to the specified class, scores less than or equal to the specified band, all the students
ListCollect2=STUDENTS. Stream (). The filter (student - & gt; CLAZZ2. Equals (student. GetClazz ()) & amp; & Student. GetScore () & lt; 75). Collect (Collectors. ToList ());
Collect2. Stream (). The forEach (student - & gt; System. The out. Println (student));
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
//method 3, access to the specified class, scores less than or equal to the specified band, all the names of the students, pay attention to the return type
ListCollect3=STUDENTS. Stream (). The filter (student - & gt; CLAZZ2. Equals (student. GetClazz ()) & amp; & Student. GetScore () & lt; 75). The map (student - & gt; Student. The getName ()). Collect (Collectors. ToList ());
Collect3. Stream (). The forEach (student - & gt; System. The out. Println (student));
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
//method 4, according to the result from low to high order, return all student
ListCollect4=STUDENTS. Stream (.) sorted (new Comparator () {
@ Override
Public int the compare (Student Student o1, o2) {
Return o1. GetScore () - o2. GetScore ();
}
}).collect(Collectors.toList());
Collect4. Stream (). The forEach (student - & gt; System. The out. Println (student));
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
//method 5, access to the specified class, scores less than or equal to the specified band, scores from high to low order, all the students
ListCollect5=STUDENTS. Stream (). The filter (student - & gt; CLAZZ2. Equals (student. GetClazz ()) & amp; & Student. GetScore () & lt; 75). Sorted (new Comparator () {
@ Override
Public int the compare (Student Student o1, o2) {
Return o1. GetScore () - o2. GetScore ();
}
}).collect(Collectors.toList());
Collect5. Stream (). The forEach (student - & gt; System. The out. Println (student));
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
//method 6, access to the specified class, scores less than or equal to the specified band, scores from high to low sorting, all of the student's student id, note that the return type
ListCollect6=STUDENTS. Stream (). The filter (student - & gt; CLAZZ2. Equals (student. GetClazz ()) & amp; & Student. GetScore () & lt; 75). Sorted (new Comparator () {
@ Override
Public int the compare (Student Student o1, o2) {
Return o2. GetScore () - o1. GetScore ();
}
}). The map (student - & gt; Student. GetNumber ()). Collect (Collectors. ToList ());
Collect6. Stream (). The forEach (student - & gt; System. The out. Println (student));
System. The out. Println (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - ");
//methods 7, access to the specified class, scores less than or equal to the specified band, all the students
Listnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnull