private ArrayList<CalculateParallelVolunteeringVO> searchProfessionalGroup(List<CollegeScoreSheet> collegeScoreSheets, String professionalGroup) throws RException { //将传来的数值进行查询 List<CollegeScoreSheet> result = new LinkedList<>(); ArrayList<CalculateParallelVolunteeringVO> searchList = new ArrayList<>(); for (CollegeScoreSheet collegeScoreSheet : collegeScoreSheets) { //因数据不多所以采用内部创建 if (collegeScoreSheet.getProfessionalGroup().contains(professionalGroup) || collegeScoreSheet.getProfessionalGroup().contains("不限选考科目")) { result.add(collegeScoreSheet); } } return getCalculateParallelVolunteeringVOS(result, searchList); }这段代码中的getCalculateParallelVolunteeringVOS(result, searchList)段里面的searchList的值是不是为null
时间: 2024-04-18 22:26:09 浏览: 12
根据你提供的代码,`getCalculateParallelVolunteeringOS(result, searchList)`方法调用中的`searchList`参数不为null。在方法调用时,`searchList`是作为参数传递给`getCalculateParallelVolunteeringVOS()`方法的。
请注意,这段代码中的`searchList`是在方法内部创建的一个空的`ArrayList<CalculateParallelVolunteeringVO>`对象,并且没有添加任何元素。因此,它不是null,但也没有包含任何元素。
在`getCalculateParallelVolunteeringVOS()`方法中,可能会对`searchList`进行一些操作,例如向其中添加元素或对其进行其他处理。你需要查看`getCalculateParallelVolunteeringVOS()`方法的实现来确定`searchList`在方法内部是否为null或被修改。
如果你希望确保在`getCalculateParallelVolunteeringVOS()`方法中的`searchList`不为null,你可以在调用该方法之前进行空指针检查,或在方法内部进行相应的初始化操作。
相关问题
private ArrayList<CalculateParallelVolunteeringVO> searchProfessionalGroup(List<CollegeScoreSheet> collegeScoreSheets, String professionalGroup) throws RException { //将传来的数值进行查询 List<CollegeScoreSheet> result = new LinkedList<>(); ArrayList<CalculateParallelVolunteeringVO> searchList = new ArrayList<>(); for (CollegeScoreSheet collegeScoreSheet : collegeScoreSheets) { //因数据不多所以采用内部创建 if (collegeScoreSheet.getProfessionalGroup().contains(professionalGroup) || collegeScoreSheet.getProfessionalGroup().contains("不限选考科目")) { result.add(collegeScoreSheet); } } return getCalculateParallelVolunteeringVOS(result, searchList); }这段代码中searchList的值是不是空值2
根据你提供的代码,`searchList`是在方法内部创建的一个`ArrayList<CalculateParallelVolunteeringVO>`对象。在代码中,确实没有给`searchList`赋予任何初始值或添加任何元素的操作。
因此,在这段代码中,`searchList`的初始值是一个空的`ArrayList<CalculateParallelVolunteeringVO>`对象。它不是`null`,但也没有包含任何元素。
请注意,作为局部变量,在每次调用`searchProfessionalGroup()`方法时,都会重新创建一个新的空的`searchList`对象。如果你希望在多次调用该方法时保留之前的结果,需要在方法外部进行适当的管理和处理。
如果你需要在方法内部对`searchList`进行操作,例如添加元素或对其进行其他处理,请确保在使用之前先进行初始化或添加所需的元素。
学生管理系统 学生Student(属性封装){ id:Long唯一 学号:String,唯一 姓名:String 电话:String,唯一 年龄:Integer 性别:Integer、Boolean 爱好:String[] 班级:Class } 班级Class(属性封装){ id:Long唯一 班级名:String } Student、Class增删改查(使用接口、创建接口实现类)(合理使用异常处理) 学生 增(id自增) 删(根据id删除) 改(根据id修改) 查(根据学号查询、姓名模糊查询、查询全部) 班级 增(id自增) 删(根据id删除) 改(根据id修改) 查(根据班级名模糊查询) 导出文档(两个文档 学号+姓名+学生信息 例:22013213+张三+学生信息 学号+姓名+班级信息 例:22013213+张三+班级信息 )完整代码生成
很高兴为您解答这个问题。以下是Java语言实现的学生管理系统代码:
Student.java:
```java
public class Student {
private Long id;
private String studentNumber;
private String name;
private String phone;
private Integer age;
private Integer gender;
private String[] hobbies;
private Class clazz;
public Student(Long id, String studentNumber, String name, String phone, Integer age, Integer gender, String[] hobbies, Class clazz) {
this.id = id;
this.studentNumber = studentNumber;
this.name = name;
this.phone = phone;
this.age = age;
this.gender = gender;
this.hobbies = hobbies;
this.clazz = clazz;
}
// getter and setter methods
}
```
Class.java:
```java
public class Class {
private Long id;
private String name;
public Class(Long id, String name) {
this.id = id;
this.name = name;
}
// getter and setter methods
}
```
StudentService.java:
```java
import java.util.List;
public interface StudentService {
void addStudent(Student student) throws Exception;
void deleteStudent(Long id) throws Exception;
void updateStudent(Student student) throws Exception;
Student getStudentByStudentNumber(String studentNumber) throws Exception;
List<Student> getStudentsByName(String name) throws Exception;
List<Student> getAllStudents() throws Exception;
void exportStudentInfo() throws Exception;
}
```
ClassService.java:
```java
import java.util.List;
public interface ClassService {
void addClass(Class clazz) throws Exception;
void deleteClass(Long id) throws Exception;
void updateClass(Class clazz) throws Exception;
List<Class> getClassesByName(String name) throws Exception;
void exportClassInfo() throws Exception;
}
```
StudentServiceImpl.java:
```java
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.List;
public class StudentServiceImpl implements StudentService {
private List<Student> students = new ArrayList<>();
@Override
public void addStudent(Student student) throws Exception {
if (student.getId() == null) {
student.setId(System.currentTimeMillis());
}
for (Student s : students) {
if (s.getStudentNumber().equals(student.getStudentNumber())) {
throw new Exception("Student number already exists.");
}
if (s.getPhone().equals(student.getPhone())) {
throw new Exception("Phone number already exists.");
}
}
students.add(student);
}
@Override
public void deleteStudent(Long id) throws Exception {
for (int i = 0; i < students.size(); i++) {
if (students.get(i).getId().equals(id)) {
students.remove(i);
return;
}
}
throw new Exception("Student not found.");
}
@Override
public void updateStudent(Student student) throws Exception {
for (int i = 0; i < students.size(); i++) {
if (students.get(i).getId().equals(student.getId())) {
students.set(i, student);
return;
}
}
throw new Exception("Student not found.");
}
@Override
public Student getStudentByStudentNumber(String studentNumber) throws Exception {
for (Student student : students) {
if (student.getStudentNumber().equals(studentNumber)) {
return student;
}
}
throw new Exception("Student not found.");
}
@Override
public List<Student> getStudentsByName(String name) {
List<Student> result = new ArrayList<>();
for (Student student : students) {
if (student.getName().contains(name)) {
result.add(student);
}
}
return result;
}
@Override
public List<Student> getAllStudents() {
return students;
}
@Override
public void exportStudentInfo() throws Exception {
FileOutputStream fos = new FileOutputStream("student_info.txt");
OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");
for (Student student : students) {
osw.write(student.getStudentNumber() + "+" + student.getName() + "+");
osw.write("id:" + student.getId() + ",");
osw.write("phone:" + student.getPhone() + ",");
osw.write("age:" + student.getAge() + ",");
osw.write("gender:" + student.getGender() + ",");
osw.write("hobbies:[");
for (int i = 0; i < student.getHobbies().length; i++) {
if (i != 0) {
osw.write(",");
}
osw.write(student.getHobbies()[i]);
}
osw.write("],");
osw.write("class:" + student.getClazz().getName());
osw.write("\r\n");
}
osw.close();
fos.close();
}
}
```
ClassServiceImpl.java:
```java
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.List;
public class ClassServiceImpl implements ClassService {
private List<Class> classes = new ArrayList<>();
@Override
public void addClass(Class clazz) throws Exception {
if (clazz.getId() == null) {
clazz.setId(System.currentTimeMillis());
}
for (Class c : classes) {
if (c.getName().equals(clazz.getName())) {
throw new Exception("Class name already exists.");
}
}
classes.add(clazz);
}
@Override
public void deleteClass(Long id) throws Exception {
for (int i = 0; i < classes.size(); i++) {
if (classes.get(i).getId().equals(id)) {
classes.remove(i);
return;
}
}
throw new Exception("Class not found.");
}
@Override
public void updateClass(Class clazz) throws Exception {
for (int i = 0; i < classes.size(); i++) {
if (classes.get(i).getId().equals(clazz.getId())) {
classes.set(i, clazz);
return;
}
}
throw new Exception("Class not found.");
}
@Override
public List<Class> getClassesByName(String name) {
List<Class> result = new ArrayList<>();
for (Class clazz : classes) {
if (clazz.getName().contains(name)) {
result.add(clazz);
}
}
return result;
}
@Override
public void exportClassInfo() throws Exception {
FileOutputStream fos = new FileOutputStream("class_info.txt");
OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF-8");
for (Class clazz : classes) {
osw.write(clazz.getId() + "+" + clazz.getName() + "+");
osw.write("\r\n");
}
osw.close();
fos.close();
}
}
```
以上就是学生管理系统的全部代码,包括学生和班级的类定义、服务接口定义和服务实现类定义。其中,学生服务实现类StudentServiceImpl和班级服务实现类ClassServiceImpl都实现了相应的增删改查方法,并且在学生服务实现类中实现了导出学生信息的方法和在班级服务实现类中实现了导出班级信息的方法。同时,这些服务实现类也合理地使用了异常处理。