Week 1-8: Spring Boot 学习计划完整项目

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-04-29 23:45:17 +08:00
commit f95aa18724
201 changed files with 18595 additions and 0 deletions
--- a/week3/src/main/java/com/learn/service/jpa/StudentJpaService.java
+++ b/week3/src/main/java/com/learn/service/jpa/StudentJpaService.java
@@ -0,0 +1,101 @@
+package com.learn.service.jpa;
+
+import com.learn.entity.Student;
+import com.learn.repository.jpa.StudentJpaRepository;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Sort;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * JPA 版本的学生服务
+ *
+ * @Transactional：声明式事务。方法执行过程中如果抛出 RuntimeException，
+ *                 所有数据库操作会自动回滚。保证数据一致性。
+ *                 readOnly=true 表示只读，性能更好（跳过脏检查）。
+ */
+@Service
+public class StudentJpaService {
+
+    private final StudentJpaRepository repository;
+
+    public StudentJpaService(StudentJpaRepository repository) {
+        this.repository = repository;
+    }
+
+    // ==================== 增删改查 ====================
+
+    @Transactional
+    public Student add(Student student) {
+        return repository.save(student);  // JPA: save() 同时用于新增和更新
+    }
+
+    @Transactional(readOnly = true)
+    public List<Student> list() {
+        return repository.findAll(Sort.by(Sort.Direction.DESC, "score"));
+    }
+
+    @Transactional(readOnly = true)
+    public Optional<Student> getById(Long id) {
+        return repository.findById(id);
+    }
+
+    @Transactional
+    public Optional<Student> update(Long id, Student updated) {
+        return repository.findById(id).map(existing -> {
+            if (updated.getName() != null) existing.setName(updated.getName());
+            if (updated.getAge() > 0) existing.setAge(updated.getAge());
+            if (updated.getEmail() != null) existing.setEmail(updated.getEmail());
+            if (updated.getScore() >= 0) existing.setScore(updated.getScore());
+            // JPA 的 save: 有 ID 且存在则更新，无 ID 则新增
+            return repository.save(existing);
+        });
+    }
+
+    @Transactional
+    public boolean delete(Long id) {
+        if (repository.existsById(id)) {
+            repository.deleteById(id);
+            return true;
+        }
+        return false;
+    }
+
+    // ==================== 搜索 ====================
+
+    @Transactional(readOnly = true)
+    public List<Student> searchByKeyword(String keyword) {
+        return repository.searchByKeyword(keyword);
+    }
+
+    @Transactional(readOnly = true)
+    public List<Student> findByName(String name) {
+        return repository.findByNameContaining(name);
+    }
+
+    // ==================== 分页（第 5 天） ====================
+
+    @Transactional(readOnly = true)
+    public Page<Student> page(int pageNum, int pageSize) {
+        // JPA 分页：PageRequest.of(页码从0开始, 每页条数, 排序)
+        PageRequest pageRequest = PageRequest.of(pageNum - 1, pageSize,
+                Sort.by(Sort.Direction.DESC, "score"));
+        return repository.findAll(pageRequest);
+    }
+
+    // ==================== 统计 ====================
+
+    @Transactional(readOnly = true)
+    public long count() {
+        return repository.count();
+    }
+
+    @Transactional(readOnly = true)
+    public long countByScoreRange(int min, int max) {
+        return repository.countByScoreRange(min, max);
+    }
+}