Spring Boot 菜鸟教程 4 JDBC

GitHub

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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>4.0.0modelVersion>

    <groupId>com.jege.spring.bootgroupId>
    <artifactId>spring-boot-jdbcartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <packaging>jarpackaging>

    <name>spring-boot-jdbcname>
    <url>http://maven.apache.orgurl>

    
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>1.4.1.RELEASEversion>
        <relativePath />
    parent>

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

    <dependencies>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-jdbcartifactId>
        dependency>

        
        <dependency>
            <groupId>com.h2databasegroupId>
            <artifactId>h2artifactId>
            <scope>runtimescope>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>

    dependencies>

    <build>
        <finalName>spring-boot-jdbcfinalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.pluginsgroupId>
                <artifactId>maven-compiler-pluginartifactId>
                <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 [email protected]
 * @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 [email protected]
 * @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 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 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 [email protected]
 * @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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