Java笔记：JDBC传统数据库访问和SpringData入门（2）-阿里云开发者社区

Java笔记：JDBC传统数据库访问和SpringData入门（2）

2022-09-12 92

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简介： Java笔记：JDBC传统数据库访问和SpringData入门

2、Spring JdbcTemplate

（1）添加依赖

<!-- spring-jdbc -->
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jdbc</artifactId>
  <version>5.3.1</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>5.3.1</version>
</dependency>

（2）配置beans.xml

<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/data"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <bean id="studentDao" class="com.mouday.dao.impl.StudentDaoSpringJdbcImpl">
        <property name="jdbcTemplate" ref="jdbcTemplate"/>
    </bean>
</beans>

（3）Dao实现类

package com.mouday.dao.impl;
import com.mouday.dao.StudentDao;
import com.mouday.domain.Student;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.PreparedStatementCreator;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
/**
 * 学生访问接口实现类
 */
public class StudentDaoSpringJdbcImpl implements StudentDao {
    private JdbcTemplate jdbcTemplate;
    public JdbcTemplate getJdbcTemplate() {
        return jdbcTemplate;
    }
    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }
    @Override
    public List<Student> query() {
        List<Student> students = new ArrayList<>();
        String sql = "select id, name, age from student";
        jdbcTemplate.query(sql, new RowCallbackHandler() {
            @Override
            public void processRow(ResultSet resultSet) throws SQLException {
                Integer id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                Integer age = resultSet.getInt("age");
                Student student = new Student();
                student.setId(id);
                student.setName(name);
                student.setAge(age);
                students.add(student);
            }
        });
        return students;
    }
    @Override
    public Integer insert(Student student) {
        String sql = "insert into student (name, age) values (?, ?)";
        KeyHolder keyHolder = new GeneratedKeyHolder();
        jdbcTemplate.update(new PreparedStatementCreator() {
            @Override
            public PreparedStatement createPreparedStatement(Connection connection) throws SQLException {
                PreparedStatement ps = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
                ps.setString(1, student.getName());
                ps.setInt(2, student.getAge());
                return ps;
            }
        }, keyHolder);
        return keyHolder.getKey().intValue();
    }
}

测试类

package com.mouday;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import javax.sql.DataSource;
public class DataSourceTest {
    ApplicationContext context = null;
    @Before
    public void setup() {
        System.out.println("StudentDaoSpringJdbcImplTest.setup");
        context = new ClassPathXmlApplicationContext("beans.xml");
    }
    @After
    public void tearDown() {
        System.out.println("StudentDaoSpringJdbcImplTest.tearDown");
        context = null;
    }
    @Test
    public void testDataSource() {
        DataSource dataSource = context.getBean("dataSource", DataSource.class);
        System.out.println(dataSource);
        Assert.assertNotNull(dataSource);
    }
    @Test
    public void testJdbcTemplate() {
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        System.out.println(jdbcTemplate);
        Assert.assertNotNull(jdbcTemplate);
    }
}
package com.mouday.dao.impl;
import com.mouday.dao.StudentDao;
import com.mouday.domain.Student;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.util.List;
public class StudentDaoSpringJdbcImplTest {
    ApplicationContext context = null;
    StudentDao studentDao = null;
    @Before
    public void setup() {
        System.out.println("StudentDaoSpringJdbcImplTest.setup");
        context = new ClassPathXmlApplicationContext("beans.xml");
        studentDao = context.getBean("studentDao", StudentDao.class);
    }
    @After
    public void tearDown() {
        System.out.println("StudentDaoSpringJdbcImplTest.tearDown");
        context = null;
        studentDao = null;
    }
    @Test
    public void testQuery() {
        List<Student> students = studentDao.query();
        System.out.println(students);
    }
    @Test
    public void testInsert() {
        Student student = new Student();
        student.setName("曹操");
        student.setAge(50);
        Integer id = studentDao.insert(student);
        System.out.println(id);
    }
}

3、优缺点分析

弊端：

Dao有大量代码

DaoImpl有重复代码

三、SpringData 快速开始

1、开发环境搭建

依赖

 <dependency>
  <groupId>org.springframework.data</groupId>
  <artifactId>spring-data-jpa</artifactId>
  <version>2.4.0</version>
</dependency>
<dependency>
  <groupId>org.hibernate</groupId>
  <artifactId>hibernate-entitymanager</artifactId>
  <version>5.4.24.Final</version>
</dependency>

配置beans-jpa.xml

<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/data/jpa
        http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    <!--1 配置数据源-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/data"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </bean>
    <!--2 配置EntityManagerFactory-->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
        </property>
        <property name="packagesToScan" value="com.mouday"/>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
    </bean>
    <!--3 配置事务管理器-->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>
    <!--4 配置支持注解的事务-->
    <tx:annotation-driven transaction-manager="transactionManager"/>
    <!--5 配置spring data-->
    <jpa:repositories base-package="com.mouday" entity-manager-factory-ref="entityManagerFactory"/>
    <context:component-scan base-package="com.mouday"/>
</beans>

定义实体

package com.mouday.domain;
import javax.persistence.*;
/**
 * 雇员表 先开发实体->自动生成数据表
 */
@Entity
public class Employee {
    private Integer id;
    private String name;
    private Integer age;
    // 主键自增
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    @Id
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    @Column(length = 20)
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}
;

自动建表测试

package com.mouday;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import javax.sql.DataSource;
public class SpringDataJpaTest {
    ApplicationContext context = null;
    @Before
    public void setup() {
        System.out.println("StudentDaoSpringJdbcImplTest.setup");
        context = new ClassPathXmlApplicationContext("beans-jpa.xml");
    }
    @After
    public void tearDown() {
        System.out.println("StudentDaoSpringJdbcImplTest.tearDown");
        context = null;
    }
    @Test
    public void testEntityManagerFactory() {
    }
}

2、Spring Data JPA 开发

定义接口

package com.mouday.repository;

import com.mouday.domain.Employee;

import org.springframework.data.repository.Repository;

public interface EmployeeRepository extends Repository<Employee, Integer> {

public Employee findByName(String name);

}

插入数据

package com.mouday.repository;
import com.mouday.domain.Employee;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class EmployeeRepositoryTest {
    ApplicationContext context = null;
    EmployeeRepository repository = null;
    @Before
    public void setup() {
        System.out.println("StudentDaoSpringJdbcImplTest.setup");
        context = new ClassPathXmlApplicationContext("beans-jpa.xml");
        repository = context.getBean(EmployeeRepository.class);
    }
    @After
    public void tearDown() {
        System.out.println("StudentDaoSpringJdbcImplTest.tearDown");
        context = null;
    }
    @Test
    public void testFindByName() {
        Employee employee = repository.findByName("刘备");
        System.out.println(employee);
    }
}

SpringDATA：

Repository核心

Repository Definition 定义

Repository Query Specifications 查询规则规范技术参数

Query Annotation 查询注解

Update/Delete/Transaction 对事务的细粒度优秀支持

Java笔记：JDBC传统数据库访问和SpringData入门（2）

三、SpringData 快速开始

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Java笔记：JDBC传统数据库访问和SpringData入门（2）

三、SpringData 快速开始

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