UserJpaRepository

/**
* 不仅继承了 PagingAndSortingRepository 同时继承了 QueryByExampleExecutor（示例匹配器）
*/
public interface UserJpaRepository extends JpaRepository<User, Long> {
}
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UserJpaRepositoryTests：

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserJpaRepositoryTests {

@Autowired
private UserJpaRepository userJpaRepository;

/**
* 执行秒数：49422 49145
* 批量插入数据
*/
@Test
public void BatchSave() {
long startTime = System.currentTimeMillis();
List<User> list = new ArrayList<User>();
for (int i = 0; i < 60000; i++) {
User user = new User();
user.setName("ljk" + i);
user.setAge(i);
user.setAddress("address" + i);
list.add(user);
if (i % 100 == 0) {
userJpaRepository.saveAll(list);
list.clear();
}
}
long endTime = System.currentTimeMillis();
System.out.println("执行秒数：" + (endTime - startTime));
}

/**
* 执行秒数：48053 48394 执行速度比BatchSave 要快
* 批量保存数据 （高效处理方式）减少大事物的提交
*/
@Test
public void BatchSaveBest() {
long startTime = System.currentTimeMillis();
List<User> list = new ArrayList<User>();
for (int i = 0; i < 60000; i++) {
User user = new User();
user.setName("ljk" + i);
list.add(user);
if (i % 100 == 0) {
userJpaRepository.saveAll(list);
userJpaRepository.flush();
list.clear();
}
}
long endTime = System.currentTimeMillis();
System.out.println("执行秒数：" + (endTime - startTime));
}

/**
* 查询所有数据
*/
@Test
public void findAll() {
List<User> userlists = userJpaRepository.findAll();
Assert.assertTrue(userlists.size() > 0);
}

/**
* 根据 age 排序查询
*/
@Test
public void findALLSortAge() {
List<User> lists = userJpaRepository.findAll(Sort.by(Sort.Direction.ASC, "age"));
for (User list : lists) {
System.out.println(list);
}
}

/**
* 分页查询
*/
@Test
public void findAllByPage() {
PageRequest pageRequest = new PageRequest(0, 1);
Page<User> userPage = userJpaRepository.findAll(pageRequest);
Assert.assertTrue(userPage.getContent().size() == 1);
}

/**
* 分页排序查询
*/
@Test
public void findAllByPageAndSort() {
PageRequest pageRequest = new PageRequest(0, 3, Sort.by(Sort.Direction.ASC, "age"));
Page<User> userPage = userJpaRepository.findAll(pageRequest);
List<User> userList = userPage.getContent();
for (User user : userList) {
System.out.println(user);
}
}

/**
* 根据id 的集合获取所有数据
*/
@Test
public void findAllByIds() {
List<Long> ids = new ArrayList<Long>();
ids.add(1L);
ids.add(2L);
ids.add(3L);
ids.add(4L);
List<User> userList = userJpaRepository.findAllById(ids);
System.out.println(userList);
}

/**
* 批量删除所有数据
*/
@Test
public void deleteAllInBatch() {
userJpaRepository.deleteAllInBatch();
}

/**
* 保存数据并刷新缓存
*/
@Test
public void saveAndFlush() {
User user = new User();
user.setName("ljk");
user.setAge(18);
user.setAddress("beijing");
user.setSex("1");
User result = userJpaRepository.saveAndFlush(user);
Assert.assertNotNull(result);
}

/**
* 批量删除
*/
@Test
public void deleteInBatch() {
List<User> userList = new ArrayList<User>();
User user = new User();
user.setId(1l);
userList.add(user);
User user2 = new User();
user2.setId(2l);
userList.add(user2);
User user3 = new User();
user3.setId(3l);
userList.add(user3);
User user4 = new User();
user4.setId(4l);
userList.add(user4);
userJpaRepository.deleteInBatch(userList);
}

/**
* 根据id 获取数据
*/
@Test
public void getOne() {
User user = userJpaRepository.findById(1L).get();
System.out.println(user);
}

/**
* 示例匹配器 ExampleMatcher
*/
@Test
public void findUserByExam() {
User user = new User();
user.setName("ljk");
List<User> list = userJpaRepository.findAll(Example.of(user));
System.out.println(list);
}

/**
* 模糊查询
*/
@Test
public void findUserByExamQuery() {
User user = new User();
user.setName("ljk");
user.setAddress("beijing");
user.setAge(18);
ExampleMatcher matcher = ExampleMatcher.matching()
.withMatcher("name", ExampleMatcher.GenericPropertyMatchers.startsWith())//模糊查询匹配开头，即{username}%
.withMatcher("address", ExampleMatcher.GenericPropertyMatchers.contains())//全部模糊查询，即%{address}%
.withIgnorePaths("id");//忽略字段，即不管id是什么值都不加入查询条件
Example<User> example = Example.of(user, matcher);
List<User> userList = userJpaRepository.findAll(example);
System.out.println(userList);
}
}