SpringBoot数据库访问工具(JdbcTemplate、MyBatis、JPA、Hibernate)

SpringBoot数据库访问

关系型数据库访问（RDBMS）

采用JdbcTemplate、MyBatis、JPA、Hibernate等技术。

一、JdbcTemplate工具

1.在pom.xml添加boot-starter-jdbc定义<dependencies> 数据库驱动

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>　　　　<version>2.0.1.RELEASE</version> 　 </dependency>

    <dependency>
        <groupId>com.oracle</groupId>
        <artifactId>ojdbc6</artifactId>
        <version>11.2.0.3</version>
    </dependency>

</dependencies>

2.在application.properties添加链接参数定义

spring.datasource.username=SCOTT
spring.datasource.password=TIGER
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:XE
spring.datasource.driverClassName=oracle.jdbc.OracleDriver

3.根据DEPT表编写Dept实体类

public class Dept implements Serializable{
    private Integer deptno;
    private String dname;
    private String loc;
    //set和get省略
}

4.定义DeptDao接口

public interface DeptDao {
    public List<Dept> findAll();
}

5.定义JdbcDeptDao实现类

@Repository("deptDao")
public class JdbcDeptDao implements DeptDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    public List<Dept> findAll() {
        String sql = "select * from DEPT";
        //BeanPropertyRowMapper功能同名加载。查询结果集列名和实体类属性名一致
        RowMapper<Dept> rowMapper = new BeanPropertyRowMapper<Dept>(Dept.class);
        List<Dept> list = jdbcTemplate.query(sql, rowMapper);
        return list;
    }

}

6.定义主启动类，开启自动配置和扫描等功能

@SpringBootApplication
public class MyBootApplication {

}

7.测试程序

public static void main(String[] args) {
    ApplicationContext ac = 
        SpringApplication.run(MyBootApplication.class);
    DeptDao deptDao = ac.getBean("deptDao",DeptDao.class);
    List<Dept> list = deptDao.findAll();
    for(Dept dept:list){
        System.out.println(dept.getDeptno()
            +" "+dept.getDname()+" "+dept.getLoc());
    }
}

二、MyBatis工具

在pom.xml添加boot-starter-jdbc、mybatis-boot定义

<parent>    <-- 设置boot版本-->
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.1.RELEASE</version>
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>

    <dependency>　　　　<!--数据库访问基于jdbc -->
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

    <dependency>　　    <!-- 数据库驱动包 -->
        <groupId>com.oracle</groupId>
        <artifactId>ojdbc6</artifactId>
        <version>11.2.0.3</version>
    </dependency>

    <!-- mybatis、mybatis-spring、autocofigurer -->
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.0</version>
    </dependency>

</dependencies>

2.在application.properties添加数据库连接参数定义

spring.datasource.username=SCOTT
spring.datasource.password=TIGER
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:XE
spring.datasource.driverClassName=oracle.jdbc.OracleDriver

3.根据DEPT表定义Dept实体类

同上

4.定义Mapper映射器DeptDao接口、利用注解定义SQL

public interface DeptDao {

    @Select("select * from DEPT")
    public List<Dept> selectAll();

    @Select("select * form DEPT where DEPTNO=#{no}")
    public Dept selectById(int id);

    @Insert("insert into DEPT(DEPTNO,DNAME,LOC) values (#{deptno},#{dname},#{loc})")
    public void save(Dept dept);

}

5.定义主启动类，添加MapperScan标记

@SpringBootApplication
@MapperScan(basePackages={"cn.xdl.dao"})
public class MyBootApplication {

}

6.测试程序

public static void main(String[] args) {
    ApplicationContext ac = 
        SpringApplication.run(MyBootApplication.class, args);
    DeptDao deptDao = ac.getBean("deptDao",DeptDao.class);
    List<Dept> list = deptDao.selectAll();
    for(Dept dept:list){
        System.out.println(dept.getDeptno()+" "+dept.getDname());
    }
}

7.追加pageHelper分页处理

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper-spring-boot-starter</artifactId>
    <version>1.2.3</version>
</dependency>

然后在调用查询方法前，执行下PageHelper.startPage()方法即可

PageHelper.startPage(2, 3);
List<Dept> list = deptDao.selectAll();

Mybatis使用注意问题：

SQL参数使用#{}和${}的区别
- 采用#{}格式，预编译SQL执行机制，SQL发送时采用?
- ${}采用Statement执行机制，参数值拼到SQL中
- SQL字段值位置使用#{}，字段名或表名位置使用${}
异常："无效列类型:1111"

参数#{}遇到null值情况，会提示上述异常。在可能为null参数位置，使用#{}时，需要指定jdbcType属性，例如#{xx,jdbcType=XXX}

三、Hibernate工具（略）

四、JPA工具

1.在pom.xml追加boot-jdbc、boot-data-jpa包定义、数据库驱动

<parent>　　　<!-- 设置boot版本控制 -->
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.1.RELEASE</version>
</parent>

<properties>　　<!-- 设置字符集utf-8 jre版本1.8-->
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>

    <dependency>　　　　<!-- jpa基于jdbc -->
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

    <dependency>　　　　<!-- 数据库驱动 -->
        <groupId>com.oracle</groupId>
        <artifactId>ojdbc6</artifactId>
        <version>11.2.0.3</version>
    </dependency>

    <dependency>　　　　<!-- jpa -->
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

</dependencies>

2.在application.properties文件追加数据库连接参数定义

spring.datasource.username=SCOTT
spring.datasource.password=TIGER
spring.datasource.url=jdbc:oracle:thin:@localhost:1521:XE
spring.datasource.driverClassName=oracle.jdbc.OracleDriver

3.根据DEPT表编写Dept实体类，并追加映射注解标记（可用jpa逆向生成工程）

@Entity
@Table(name="DEPT")
public class Dept implements Serializable{

    @Id
    @Column(name="DEPTNO")
    private Integer deptno;

    @Column(name="DNAME")
    private String dname;

    @Column(name="LOC")
    private String loc;

    //省略set和get方法       

}

4.定义DeptDao接口，可以继承JpaRepository

public interface DeptDao extends JpaRepository<Dept, Integer>{　　//Dept 为eitity类型 Integer为主键类型

}

Repository：顶级接口，无任何操作

CrudRepository：继承了Repository，增加了增删改查操作方法

PagingAndSortingRepository：继承CrudRepository，增加了分页和排序操作

JpaRepository：继承了PagingAndSortingRepository，增加批处理操作

5.测试程序

public static void main(String[] args) {
    ApplicationContext ac = 
        SpringApplication.run(MyBootApplication.class, args);
    DeptDao deptDao = ac.getBean("deptDao",DeptDao.class);
    List<Dept> list = deptDao.findAll();
    for(Dept dept:list){
        System.out.println(dept.getDeptno()+" "+dept.getDname());
    }
}

来源：https://www.cnblogs.com/xiaoka000/p/9691436.html

标签

jdbc