一、springboot中spring data jpa的配置

pom.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.xym</groupId>
    <artifactId>jpa-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.6.RELEASE</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>
</project>

application.yml

spring:
  datasource:
    url: jdbc:mysql://192.168.1.70:3306/jpa
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: 123456
  jpa:
    hibernate:
      ddl-auto: update # update 拥有表结构就什么也不做,create不管有没有都重新创建,create-drop 退出时清空表 none 什么也不做
    show-sql: true   #配置打印sql语句
    database: mysql  #指明数据库
    properties:
      hibernate.dialect: org.hibernate.dialect.MySQL55Dialect #设置hibernate数据库的方言

测试类基础模板

@RunWith(SpringRunner.class)
@SpringBootTest
public class ObjectQuery {
    
    @Autowired
    private Dao dao;
}

二、spring data jpa基础增删改查

实体bean

@Entity
@Table(name="t_book")
//@DynamicInsert
//@DynamicUpdate(value = true)//只对于更新的字段设置值
public class Book {
    
    @Id //id表明是主键
    //IDENTITY:主键由数据库自动生成（主要是自动增长型） mysql
    //SEQUENCE：根据底层数据库的序列来生成主键，条件是数据库支持序列。
    //AUTO：主键由程序控制
    //TABLE：使用一个特定的数据库表格来保存主键
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    //Column注解可以定制表中的字段属性 name 表示字段名称 nullable表示非空
    @Column(name = "book_name",nullable = false)
    private String name;
    private Double price;
    //自动开启了驼峰配置
    private String bookAuthor;
    @Transient //表示生成表的时候,该属性被忽略,不生成相应字段
    private String description;
}

dao层代码

public interface BookDao extends JpaRepository<Book,Long>, JpaSpecificationExecutor<Book> {
    
 
}

测试代码

@Autowired
    private BookDao bookDao;

    @Test
    @Transactional //测试懒加载,需要事务的支持
    public void Test(){
    
        //org.hibernate.LazyInitializationException: could not initialize proxy [com.xym.pojo.Book#1] - no Session
        Book one = bookDao.getOne( 1L);//懒加载什么时候用是么时候查询
        System.out.println(one);
    }

    @Test  //查询实时生效
    public void Test2(){
    
        Optional<Book> byId = bookDao.findById(1L);
    }

    @Test//测试保存
    public void save(){
    
        Book book = new Book("四世同堂",5.88,"老舍");
        bookDao.save(book);
        System.out.println(book.getId());
    }

    @Test//测试更新
    public void update(){
    
        Optional<Book> book = bookDao.findById(9L);
        /*Book book = new Book("骆驼",null,"老舍");
        book.setId(9L);*/
        Book book1 = book.get();
        book1.setName("祥子");
        book1.setBookAuthor("老舍");
        bookDao.save(book1);
        //System.out.println(book.getId());
    }

三、spring data jpa利用原生sql或者jpql执行数据库操作

dao层代码

public interface BookDao extends JpaRepository<Book,Long>, JpaSpecificationExecutor<Book> {
    
    /*//利用jpql或者sql语句完成查询
    参数的接收方式分为两种:
    一、按照参数的标识来传递参数
    二、按照参数的位置来传递参数
    */
    @Query(value = "select * from t_book b where b.id = :id and b.book_author =:author",nativeQuery = true)
    List<Book> getBooksByIdAndAuthorByParam(@Param("author") String author, @Param("id") Long id);

    @Query(value = "select * from t_book b where b.id = ?2 and b.book_author =?1",nativeQuery = true)
    List<Book> getBooksByIdAndAuthorByPlace( String author,  Long id);

    @Query(value = "from Book b where b.id = ?2 and b.bookAuthor =?1")
    List<Book> getBooksByIdAndAuthorByPlaceJPQL( String author,  Long id);

    @Modifying//利用次注解表明需要加入事务
    @Query(value = "update Book b set b.bookAuthor =?1 where b.id=?2")
    int updateBookAuthorById( String author,Long id);
}

测试部分代码

@Test//参数标识接收参数的方式
    public void nativeParam1(){
    
        List<Book> books = bookDao.getBooksByIdAndAuthorByParam("老舍", 9L);
        for (Book b:
             books) {
    
            System.out.println(b);
        }
    }

    @Test//参数接收方式
    public void nativeParam2(){
    
        List<Book> books = bookDao.getBooksByIdAndAuthorByPlace("老舍", 8L);
        for (Book b:
                books) {
    
            System.out.println(b);
        }
        //System.out.println(book.getId());
    }

    @Test//参数标识接收参数的方式
    public void jPQLParam1(){
    
        List<Book> books = bookDao.getBooksByIdAndAuthorByPlaceJPQL("老舍", 9L);
        for (Book b:
                books) {
    
            System.out.println(b);
        }
    }

    @Test//利用sql语句或者jpql语句完成更新
    @Transactional
    @Rollback(value = false)
    public void jPQLUpdate(){
    
       bookDao.updateBookAuthorById("张三",7l);
    }

四、spring data jpa根据命名规则查询

dao层代码

public interface BookDao extends JpaRepository<Book,Long>, JpaSpecificationExecutor<Book> {
    
    /*
    * 方法名的约定：
    *       findBookBy:表示单数
    *       findBooksBy:表示查询复数
     *      1.findBy | getBy + 属性名称 （根据属性名称进行精确匹配的查询=）
     *      2.findBy | getBy  + 属性名称 + “查询方式（Like | isnull）”
     *          findByCustNameLike
     *      3.多条件查询
     *          findBy | getBy  + 属性名 + “查询方式”   + “多条件的连接符（and|or）”  + 属性名 + “查询方式”
    *
    * */
    //1.findBy | getBy + 属性名称 （根据属性名称进行精确匹配的查询=）
    Book findByName(String name);

    //findBy | getBy  + 属性名称 + “查询方式（Like | isnull）”
    List<Book> getBooksByBookAuthorStartingWith(String author);
    // findBy | getBy  + 属性名 + “查询方式”   + “多条件的连接符（and|or）”  + 属性名 + “查询方式”
    List<Book> findByNameLikeAndAndBookAuthor(String name,String bookAuthor);
}

测试代码

@Test//1.findBy | getBy + 属性名称 （根据属性名称进行精确匹配的查询=）
    public void nameFindName(){
    
        Book name = bookDao.findByName("三国演义");
        System.out.println(name);
    }

    @Test//2.findBy | getBy  + 属性名称 + “查询方式（Like | isnull）”
    public void nameFindAuthorStart(){
    
        List<Book> books = bookDao.getBooksByBookAuthorStartingWith("张");
        System.out.println(books);
    }

    @Test//2.findBy | getBy  + 属性名称 + “查询方式（Like | isnull）”
    public void nameComponet(){
    
        List<Book> books = bookDao.findByNameLikeAndAndBookAuthor("%祥子%","老舍");
        System.out.println(books);
    }

注:支持的命名规范:

五、specification（规范查询，分页，动态sql）

规范查询代码

 @Test
    public void testSpec() {
    
        //匿名内部类
        /**
         * 自定义查询条件
         *      1.实现Specification接口（提供泛型：查询的对象类型）
         *      2.实现toPredicate方法（构造查询条件）
         *      3.需要借助方法参数中的两个参数（
         *          root：获取需要查询的对象属性
         *          CriteriaBuilder：构造查询条件的，内部封装了很多的查询条件（模糊匹配，精准匹配）
         *       ）
         *  案例：根据客户名称查询，查询客户名为传智播客的客户
         *          查询条件
         *              1.查询方式
         *                  cb对象
         *              2.比较的属性名称
         *                  root对象
         *
         */
        Specification<Book> spec = (Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb)-> {
    
            //1.获取比较的属性
            Path<Object> name = root.get("name");
            //第二个参数：当前需要比较的取值
            Predicate predicate = cb.equal(name, "朝花夕拾");
            /*@Override
            public Predicate toPredicate(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb) {

                Path<Object> custName = root.get("custId");
                //2.构造查询条件  ：    select * from cst_customer where cust_name = '传智播客'
                *//**
                 * 第一个参数：需要比较的属性（path对象）
                 *
                 *//*
                Predicate predicate = cb.equal(custName, "传智播客");//进行精准的匹配  （比较的属性，比较的属性的取值）
                return predicate;
            }*/
            return  predicate;
        };
        Book customer = bookDao.findOne(spec).get();
        System.out.println(customer);
    }
    @Test
    public void testSpec2(){
    
        Specification<Book> spec =(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb)-> {
    


            Path<Object> name = root.get("name");
            Path<Object> bookAuthor = root.get("bookAuthor");

            Predicate name1  = cb.equal(name,"骆驼祥子");
            //name1.
            Predicate bookAuthor1 = cb.equal(bookAuthor, "老舍");
            Predicate and = cb.or(name1, bookAuthor1);

            return and;
        };
        List<Book> all = bookDao.findAll(spec);
        System.out.println(all);
    }

    @Test
    public void testSpec3(){
    
        Specification<Book> spec =(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb)-> {
    
            Path<Object> name = root.get("name");

            Predicate predicate  = cb.like(name.as(String.class),"%祥子%");

            return predicate;
        };
        //排序查询
        Sort sort =new Sort(Sort.Direction.DESC,"id");
        List<Book> all = bookDao.findAll(spec,sort);
        System.out.println(all);
    }

    @Test
    public void testSpec4(){
    
        Specification<Book> spec =(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb)-> {
    
            Path<Object> id = root.get("id");

            Predicate predicate  = cb.gt(id.as(Long.class),0L);

            return predicate;
        };
        //排序查询
        Sort sort =new Sort(Sort.Direction.DESC,"id");
        Pageable page = PageRequest.of(0,2,sort);
        Page<Book> all = bookDao.findAll(spec, page);
        System.out.println(all.getTotalPages());
        System.out.println(all.getTotalElements());
        System.out.println(all.getContent());
    }

    @Test
    public void testSpec5(){
    
        String name = "骆驼祥子";
        String bookAuthor = "老舍";
        Specification<Book> spec =(Root<Book> root, CriteriaQuery<?> query, CriteriaBuilder cb)-> {
    
            List<Predicate> pres = new ArrayList<>();
            pres.add(cb.equal(root.get("name"),name));
            pres.add(cb.equal(root.get("bookAuthor"),bookAuthor));
            Predicate and = cb.and(pres.toArray(new Predicate[pres.size()]));
            return and;
        };
        //排序查询
        Sort sort =new Sort(Sort.Direction.DESC,"id");
        Pageable page = PageRequest.of(0,2,sort);
        Page<Book> all = bookDao.findAll(spec, page);
        System.out.println(all.getTotalPages());
        System.out.println(all.getTotalElements());
        System.out.println(all.getContent());
    }

六、多表关联查询

一对多查询

实体类

@Entity
@Table(name = "cst_customer")
public class Customer {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="cust_id")
    private Long custId;
    @Column(name="cust_address")
    private String custAddress;
    @Column(name="cust_industry")
    private String custIndustry;
    @Column(name="cust_level")
    private String custLevel;
    @Column(name="cust_name")
    private String custName;
    @Column(name="cust_phone")
    private String custPhone;
    @Column(name="cust_source")
    private String custSource;

    //配置客户和联系人之间的关系（一对多关系）
    /**
     * 使用注解的形式配置多表关系
     *      1.声明关系
     *          @OneToMany : 配置一对多关系
     *              targetEntity ：对方对象的字节码对象
     *      2.配置外键（中间表）
     *              @JoinColumn : 配置外键
     *                  name：外键字段名称
     *                  referencedColumnName：参照的主表的主键字段名称
     *
     *  * 在客户实体类上（一的一方）添加了外键了配置，所以对于客户而言，也具备了维护外键的作用
     *
     */
    /*@OneToMany(targetEntity = LinkMan.class,cascade = CascadeType.ALL)
    @JoinColumn(name = "lkm_cust_id",referencedColumnName = "cust_id")
    private Set<LinkMan> linkMans = new HashSet<>();*/

    /*@OneToMany(mappedBy ="customer")
    private Set<LinkMan> linkMans = new HashSet<>();*/
    @OneToMany(mappedBy ="customer",cascade = CascadeType.ALL,fetch = FetchType.EAGER)
    private Set<LinkMan> linkMans = new HashSet<>();
}

@Entity(name = "cst_linkman")
public class LinkMan {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "lkm_id")
    private Long lkmId; //联系人编号(主键)
    @Column(name = "lkm_name")
    private String lkmName;//联系人姓名
    @Column(name = "lkm_gender")
    private String lkmGender;//联系人性别
    @Column(name = "lkm_phone")
    private String lkmPhone;//联系人办公电话
    @Column(name = "lkm_mobile")
    private String lkmMobile;//联系人手机
    @Column(name = "lkm_email")
    private String lkmEmail;//联系人邮箱
    @Column(name = "lkm_position")
    private String lkmPosition;//联系人职位
    @Column(name = "lkm_memo")
    private String lkmMemo;//联系人备注

    /**
     * 配置联系人到客户的多对一关系
     *     使用注解的形式配置多对一关系
     *      1.配置表关系
     *          @ManyToOne : 配置多对一关系
     *              targetEntity：对方的实体类字节码
     *      2.配置外键（中间表）
     *
     * * 配置外键的过程，配置到了多的一方，就会在多的一方维护外键
     *
     */
    @ManyToOne(targetEntity = Customer.class,fetch = FetchType.LAZY)
    @JoinColumn(name = "lkm_cust_id",referencedColumnName = "cust_id")
    private Customer customer;
}

dao层代码

	只是简单的实现两个接口不做特殊说明

查询的代码

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

    @Autowired
    private CustomerDao customerDao;

    @Autowired
    private LinkManDao linkManDao;

    @Test
    @Transactional
    @Rollback(value = false)
    public void testAdd(){
    //通过客户表关联联系人
        Customer c  = new Customer();
        c.setCustName("公信科技");
        LinkMan linkMan  = new LinkMan();
        linkMan.setLkmName("肿瘤医院");
        c.getLinkMans().add(linkMan);
        //保存两条会多出一条update语句，原因是两个表都对外建进行了维护
        //设置级联后保存一个，就可以把两条数据都进行保存
        //customerDao.save(c);
        //linkManDao.save(linkMan);
        //有一方放弃外建的维护
        customerDao.save(c);
        linkManDao.save(linkMan);

    }

    @Test
    @Transactional
    @Rollback(value = false)
    public void testAdd2(){
    //通过联系人关联客户
        Customer c  = new Customer();
        c.setCustName("公信科技");
        LinkMan linkMan  = new LinkMan();
        linkMan.setLkmName("肿瘤医院");
        linkMan.setCustomer(c);
        //有一方放弃外建的维护
        customerDao.save(c);
        linkManDao.save(linkMan);
    }

    @Test
    @Transactional
    @Rollback(value = false)
    public void testAdd3(){
    //互相都添加
        Customer c  = new Customer();
        c.setCustName("公信科技");
        LinkMan linkMan  = new LinkMan();
        linkMan.setLkmName("肿瘤医院");
        linkMan.setCustomer(c);
        c.getLinkMans().add(linkMan);
        //有一方放弃外建的维护
        customerDao.save(c);
        linkManDao.save(linkMan);

    }

    @Test
    @Transactional
    @Rollback(value = false)
    public void testAdd4(){
    //级联添加
        Customer c  = new Customer();
        c.setCustName("公信科技");

        LinkMan linkMan  = new LinkMan();
        linkMan.setLkmName("肿瘤医院");
        c.getLinkMans().add(linkMan);
        //有一方放弃外建的维护
        customerDao.save(c);
    }
    @Test
    @Transactional
    @Rollback(value = false)
    public void testAdd5(){
    //级联删除与
        Customer c  = new Customer();
        c.setCustName("公信科技");
        c.setCustId(1L);
        //有一方放弃外建的维护
        customerDao.delete(c);
    }
}

多对多查询

实体bean

@Entity
@Table(name = "sys_role")
public class Role {
    

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "role_id")
    private Long roleId;
    @Column(name = "role_name")
    private String roleName;

    //配置多对多
    @ManyToMany(mappedBy = "roles")  //配置多表关系 被动添加的一方放弃外键维护关系
    private Set<User> users = new HashSet<>();
}

@Entity
@Table(name = "sys_user")
public class User {
    

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="user_id")
    private Long userId;
    @Column(name="user_name")
    private String userName;
    @Column(name="age")
    private Integer age;

    /**
     * 配置用户到角色的多对多关系
     *      配置多对多的映射关系
     *          1.声明表关系的配置
     *              @ManyToMany(targetEntity = Role.class)  //多对多
     *                  targetEntity：代表对方的实体类字节码
     *          2.配置中间表（包含两个外键）
     *                @JoinTable
     *                  name : 中间表的名称
     *                  joinColumns：配置当前对象在中间表的外键
     *                      @JoinColumn的数组
     *                          name：外键名
     *                          referencedColumnName：参照的主表的主键名
     *                  inverseJoinColumns：配置对方对象在中间表的外键
     */
    @ManyToMany(targetEntity = Role.class,cascade = CascadeType.ALL)
    @JoinTable(name = "sys_user_role",
            //joinColumns,当前对象在中间表中的外键
            joinColumns = {
    @JoinColumn(name = "sys_user_id",referencedColumnName = "user_id")},
            //inverseJoinColumns，对方对象在中间表的外键
            inverseJoinColumns = {
    @JoinColumn(name = "sys_role_id",referencedColumnName = "role_id")}
    )
    private Set<Role> roles = new HashSet<>();
}

dao层代码

	只是简单的实现两个接口不做特殊说明

查询的代码

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

    @Autowired
    private RoleDao roleDao;

    @Autowired
    private UserDao userDao;

    @Test
    @Transactional
    @Rollback(false)
    public void  testAdd() {
    
        User user = new User();
        user.setUserName("小李");
        Role role = new Role();
        role.setRoleName("java程序员");
        //配置用户到角色关系，可以对中间表中的数据进行维护     1-1
        user.getRoles().add(role);
        //配置角色到用户的关系，可以对中间表的数据进行维护     1-1
        role.getUsers().add(user);
        userDao.save(user);
        roleDao.save(role);
    }

    @Test
    @Transactional
    @Rollback(false)
    public void  testCascadeAdd2() {
    
        User user = new User();
        user.setUserName("小李");
        Role role = new Role();
        role.setRoleName("java程序员");
        //配置用户到角色关系，可以对中间表中的数据进行维护     1-1
        user.getRoles().add(role);
        userDao.save(user);
    }

    @Test
    @Transactional
    @Rollback(false)
    public void  testCascadeDelete() {
    
        userDao.deleteById(1L);
    }
}

对象查询

####查询对象

@RunWith(SpringRunner.class)
@SpringBootTest
public class ObjectQuery {
    
    @Autowired
    private CustomerDao customerDao;

    @Autowired
    private LinkManDao linkManDao;


    @Test
    @Transactional
    @Rollback(value = false)
    public void testQuery(){
    
        Customer one = customerDao.getOne(1L);
        Set<LinkMan> linkMans = one.getLinkMans();//延迟加载
        for (LinkMan l:linkMans) {
    
            System.out.println(l);
        }
    }
    @Test
    @Transactional
    @Rollback(value = false)
    public void testQuery2(){
    
       LinkMan one = linkManDao.findById(1L).get();
        Customer customer = one.getCustomer();
        System.out.println(customer);

    }
}