Spring Boot 菜鸟教程 4 JDBC

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JDBC

Java Data Base Connectivity,是一种用于执行SQL语句的Java API，可以为多种关系数据库提供统一访问，它由一组用Java语言编写的类和接口组成。不管是Hibernate，还是JPA或者MyBatis都是对JDBC做了一次封装。

Spring简化了JDBC那些内容

Spring JDBC抽象框架所带来的价值将在以下几个方面得以体现：（注：使用了Spring JDBC抽象框架之后，应用开发人员只需要完成斜体字部分的编码工作。）
- 定义数据库连接参数
- 打开数据库连接
- 声明SQL语句
- 预编译并执行SQL语句
- 遍历查询结果（如果需要的话）
- 处理每一次遍历操作
- 处理抛出的任何异常
- 处理事务
- 关闭数据库连接

项目图片

pom.xml

-只需要在pom.xml引入需要的数据库配置，就会自动访问此数据库，如果需要配置其他数据库，可以在application.properties进行添加
-默认使用org.apache.tomcat.jdbc.pool.DataSource创建连接池

<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.jege.spring.boot</groupId>
<artifactId>spring-boot-jdbc</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>spring-boot-jdbc</name>
<url>http://maven.apache.org</url>

<!-- 公共spring-boot配置，下面依赖jar文件不用在写版本号 -->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.1.RELEASE</version>
<relativePath />
</parent>

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

<dependencies>

<!-- 持久层 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

<!-- h2内存数据库 -->
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>

</dependencies>

<build>
<finalName>spring-boot-jdbc</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

模型对象User

package com.jege.spring.boot.jdbc.entity;

/**
 * @author JE哥
 * @email [e-mail]
 * @description:模型对象
 */
public class User {
private Long id;
private String name;
private Integer age;

public User() {
  }

public User(String name, Integer age) {
this.name = name;
this.age = age;
  }

持久层实现类UserDaoImpl

package com.jege.spring.boot.jdbc.dao.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import com.jege.spring.boot.jdbc.dao.IUserDao;
import com.jege.spring.boot.jdbc.entity.User;

/**
 * @author JE哥
 * @email [e-mail]
 * @description:jdbc CRUD
 */
@Repository
public class UserDaoImpl implements IUserDao {
@Autowired
  JdbcTemplate jdbcTemplate;

@Override
public void dropTable() {
    jdbcTemplate.update("drop table t_user if exists");
  }

@Override
public void createTable() {
    jdbcTemplate.update(
"create table t_user (id bigint generated by default as identity, age integer, name varchar(255), primary key (id))");
  }

@Override
public void save(User user) {
    jdbcTemplate.update("insert into t_user(name,age) values(?,?)", user.getName(), user.getAge());
  }

@Override
public List<User> findAll() {
return jdbcTemplate.query("select id,name,age from t_user", BeanPropertyRowMapper.newInstance(User.class));
  }

@Override
public void deleteAll() {
    jdbcTemplate.update("delete from t_user");
  }

@Override
public List<User> findByNameLike(String name) {
return jdbcTemplate.query("select id,name,age from t_user where name like ?", new Object[] { name },
    BeanPropertyRowMapper.newInstance(User.class));
  }

}

不需要application.properties

测试类UserDaoTest

package com.jege.spring.boot.data.jpa;

import static org.assertj.core.api.Assertions.assertThat;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.jege.spring.boot.jdbc.dao.IUserDao;
import com.jege.spring.boot.jdbc.entity.User;

/**
 * @author JE哥
 * @email [e-mail]
 * @description:
 */
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest()
public class UserDaoTest {
@Autowired
  IUserDao userDao;

// 每次执行Test之前先删除表，创建表
@Before
public void before() throws Exception {
    userDao.dropTable();
    userDao.createTable();
  }

@Test
public void save() throws Exception {
for (int i = 0; i < 10; i++) {
      User user = new User("jege" + i, 25 + i);
      userDao.save(user);
    }
  }

@Test
public void all() throws Exception {
    save();
    assertThat(userDao.findAll()).hasSize(10);
  }

@Test
public void findByName() throws Exception {
    save();
    assertThat(userDao.findByNameLike("jege%")).hasSize(10);
  }

@After
public void destroy() throws Exception {
    userDao.deleteAll();
  }

}

源码地址

https://github.com/je-ge/spring-boot

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