摘要：前言又是小師弟的投稿，確是一個(gè)喜歡技術(shù)的朋友。以下為原文今天閑的無聊看官方文檔的時(shí)候，發(fā)現(xiàn)并沒有完整的關(guān)鍵字語義翻譯。另外，關(guān)注之后在發(fā)送可領(lǐng)取免費(fèi)學(xué)習(xí)資料。

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又是小師弟的投稿，確是一個(gè)喜歡技術(shù)的朋友。以下為原文：

今天閑的無聊看 Spring Data JPA 官方文檔的時(shí)候，發(fā)現(xiàn)并沒有完整的 Jpa 關(guān)鍵字語義翻譯。所以今天寫了一篇中文文檔，如果有錯(cuò)誤，望大家輕噴。

以下為官方圖片以及示例代碼和注釋 ：

首先參照官方文檔創(chuàng)建指定數(shù)據(jù)庫

CREATE TABLE `demo_jpa`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `first_name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `last_name` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `sex` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `email` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `age` int(12) NOT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 6 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

示例代碼及注釋<參照以上順序>

/**
 * @Author: EvilSay
 * @Date: 2019/2/25 16:15
 */
public interface DemoJpaRepositories extends JpaRepository {

    //根據(jù)firstName與LastName查找(兩者必須在數(shù)據(jù)庫有)
    DemoJpa findByFirstNameAndLastName(String firstName, String lastName);

    //根據(jù)firstName或LastName查找(兩者其一有就行)
    DemoJpa findByLastNameOrFirstName(String lastName,String firstName);

    //根據(jù)firstName查找它是否存在數(shù)據(jù)庫里<類似與以下關(guān)鍵字>
    //DemoJpa findByFirstName(String firstName);
    DemoJpa findByFirstNameIs(String firstName);

    //在Age數(shù)值age到age2之間的數(shù)據(jù)
    List findByAgeBetween(Integer age, Integer age2);

    //小于指定age數(shù)值之間的數(shù)據(jù)
    List findByAgeLessThan(Integer age);

    //小于等于指定age數(shù)值的數(shù)據(jù)
    List findByAgeLessThanEqual(Integer age);

    //大于指定age數(shù)值之間的數(shù)據(jù)
    List findByAgeGreaterThan(Integer age);

    //大于或等于指定age數(shù)值之間的數(shù)據(jù)
    List findByAgeGreaterThanEqual(Integer age);

    //在指定age數(shù)值之前的數(shù)據(jù)類似關(guān)鍵字
    List findByAgeAfter(Integer age);

    //在指定age數(shù)值之后的數(shù)據(jù)類似關(guān)鍵字
    List  findByAgeBefore(Integer age);

    //返回age字段為空的數(shù)據(jù)
    List findByAgeIsNull();

    //返回age字段不為空的數(shù)據(jù)
    List findByAgeNotNull();

    /**
     * 該關(guān)鍵字我一度以為是類似數(shù)據(jù)庫的模糊查詢,
     * 但是我去官方文檔看到它里面并沒有通配符。
     * 所以我覺得它類似
     * DemoJpa findByFirstName(String firstName);
     * @see https://docs.spring.io/spring-data/jpa/docs/2.1.5.RELEASE/reference/html/#jpa.repositories
     */
    DemoJpa findByFirstNameLike(String firstName);

    //同上
    List findByFirstNameNotLike(String firstName);

    //查找數(shù)據(jù)庫中指定類似的名字(如：輸入一個(gè)名字"M" Jpa會(huì)返回多個(gè)包含M開頭的名字的數(shù)據(jù)源)<類似數(shù)據(jù)庫模糊查詢>
    List findByFirstNameStartingWith(String firstName);

    //查找數(shù)據(jù)庫中指定不類似的名字(同上)
    List findByFirstNameEndingWith(String firstName);

    //查找包含的指定數(shù)據(jù)源(這個(gè)與以上兩個(gè)字段不同的地方在與它必須輸入完整的數(shù)據(jù)才可以查詢)
    List findByFirstNameContaining(String firstName);

    //根據(jù)age選取所有的數(shù)據(jù)源并按照LastName進(jìn)行升序排序
    List findByAgeOrderByLastName(Integer age);

    //返回不是指定age的所有數(shù)據(jù)
    List findByAgeNot(Integer age);

    //查找包含多個(gè)指定age返回的數(shù)據(jù)
    List findByAgeIn(List age);

}

單元測試<已經(jīng)全部通過>

@SpringBootTest
@RunWith(SpringRunner.class)
@Slf4j
public class DemoJpaRepositoriesTest {

    @Autowired
    private DemoJpaRepositories repositories;

    @Test
    public void findByFirstNameAndLastName() {
        DemoJpa demoJpa = repositories.findByFirstNameAndLastName("May", "Eden");
        Assert.assertEquals(demoJpa.getFirstName(),"May");
    }

    @Test
    public void findByLastNameOrFirstName() {
        DemoJpa demoJpa = repositories.findByLastNameOrFirstName("Geordie", "Eden");
        Assert.assertNotEquals(demoJpa.getLastName(),"Eden");
    }

    @Test
    public void findByFirstNameIs() {
        DemoJpa demoJpa = repositories.findByFirstNameIs("amy");
        Assert.assertNull(demoJpa);
    }

    @Test
    public void findByAgeBetween() {
        List demoJpaList = repositories.findByAgeBetween(15, 17);
        Assert.assertEquals(3,demoJpaList.size());
    }

    @Test
    public void findByAgeLessThan() {
        List demoJpaList = repositories.findByAgeLessThan(17);
        Assert.assertEquals(2,demoJpaList.size());
    }

    @Test
    public void findByAgeLessThanEqual() {
        List demoJpaList = repositories.findByAgeLessThanEqual(17);
        Assert.assertEquals(3,demoJpaList.size());
    }

    @Test
    public void findByAgeGreaterThan() {
        List demoJpaList = repositories.findByAgeGreaterThan(17);
        Assert.assertEquals(2,demoJpaList.size());
    }

    @Test
    public void findByAgeGreaterThanEqual() {
        List demoJpaList = repositories.findByAgeGreaterThanEqual(17);
        Assert.assertEquals(3,demoJpaList.size());
    }

    @Test
    public void findByAgeAfter() {
        List demoJpaList = repositories.findByAgeAfter(17);
        Assert.assertEquals(2,demoJpaList.size());
    }

    @Test
    public void findByAgeBefore() {
        List demoJpaList = repositories.findByAgeBefore(17);
        Assert.assertEquals(2,demoJpaList.size());
    }

    @Test
    public void findByAgeIsNull() {
        List demoJpaList = repositories.findByAgeIsNull();
        Assert.assertEquals(0,demoJpaList.size());
    }

    @Test
    public void findByAgeNotNull() {
        List demoJpaList = repositories.findByAgeNotNull();
        Assert.assertEquals(5,demoJpaList.size());
    }

    @Test
    public void findByFirstNameLike() {
        DemoJpa demoJpa = repositories.findByFirstNameLike("May");
        Assert.assertNotNull(demoJpa);
    }

    @Test
    public void findByFirstNameNotLike() {

    }

    @Test
    public void findByFirstNameStartingWith() {
        List demoJpaList = repositories.findByFirstNameStartingWith("May");
        Assert.assertEquals(2,demoJpaList.size());
    }

    @Test
    public void findByFirstNameEndingWith() {
        List demoJpaList = repositories.findByFirstNameEndingWith("Evil");
        Assert.assertEquals(0,demoJpaList.size());
    }

    @Test
    public void findByFirstNameContaining() {
        List demoJpaList = repositories.findByFirstNameContaining("hack");
        Assert.assertEquals(0,demoJpaList.size());
    }

    @Test
    public void findByAgeOrderByLastName() {
        List demoJpaList = repositories.findByAgeOrderByLastName(18);
        for (DemoJpa demoJpaL : demoJpaList){
            log.info("數(shù)據(jù)結(jié)果"+demoJpaL.toString());
        }
    }

    @Test
    public void findByAgeNot() {
        List demoJpaList = repositories.findByAgeNot(20);
        Assert.assertEquals(5,demoJpaList.size());
    }

    @Test
    public void findByAgeIn() {
        List demoJpaList = repositories.findByAgeIn(Arrays.asList(15, 16));
        Assert.assertEquals(2,demoJpaList.size());
    }

}

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