## 保存 ~~~ User user = new User(); user.setName("jack"); Role role1 = new Role(); role1.setRole_name("物流管理員"); Role role2 = new Role(); role2.setRole_name("倉庫管理員"); user.getRoles().add(role1); user.getRoles().add(role2); role1.getUsers().add(user); role2.getUsers().add(user); entityManager.persist(user); entityManager.persist(role1); entityManager.persist(role2); ~~~ ## 級聯保存 User類: ~~~ @ManyToMany(targetEntity = Role.class, cascade = CascadeType.ALL) //設置級聯 ~~~ 代碼: ~~~ User user = new User(); user.setName("jack"); Role role1 = new Role(); role1.setRole_name("物流管理員"); Role role2 = new Role(); role2.setRole_name("倉庫管理員"); user.getRoles().add(role1); user.getRoles().add(role2); entityManager.persist(user); ~~~ ## 刪除一個角色 ~~~ User user = entityManager.find(User.class, 15L); Role role = entityManager.find(Role.class, 16L); user.getRoles().remove(role); ~~~ ## 添加一個角色 ~~~ User user = entityManager.find(User.class, 15L); Role role = entityManager.find(Role.class, 16L); user.getRoles().add(role); ~~~ ## 普通刪除 就算不配置級聯操作,普通刪除也會把中間表關聯的數據給刪除掉. ~~~ Role role = entityManager.find(Role.class, 16L); entityManager.remove(user); ~~~