spring boot 与 JdbcTemplate 一起工作(转)

原文地址 http://www.cnblogs.com/tomlxq/p/5514658.html

本文将介绍如何将spring boot 与 JdbcTemplate一起工作。

Spring对数据库的操作在jdbc上面做了深层次的封装，使用spring的注入功能，可以把DataSource注册到JdbcTemplate之中。 JdbcTemplate 是在JDBC API基础上提供了更抽象的封装，并提供了基于方法注解的事务管理能力。 通过使用SpringBoot自动配置功能并代替我们自动配置beans. 在maven中，我们需要增加spring-boot-starter-jdbc模块

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

通过这个模块为我们做了以下几件事

• tomcat-jdbc－{version}.jar为我们自动配置DataSource.

• 如果你没有定义任何DataSource，SpringBoot将会自动配置一个内存的数据库资源设置

• 如果没有设置任一个beans，SpringBoot会自动注册它

• 初始化数据库

  如果我们在classpath里定义了schema.sql和data.sql文件，springBoot将会使用这些文件自动初始化数据库(但你必须选建库)
  除了载入schema.sql和data.sql外，SpringBoot也会载入schema-${platform}.sql和data-${platform}.sql，如果在你的classpath下存在的话。

  spring.datasource.schema=xxxx-db.sql 可以定义你的建库文件
  spring.datasource.data=xxxx-data.sql  可以定义你的数据文件
  spring.datasource.initialize＝true|false 可以决定是不是要初始化这些数据库文件
  spring.datasource.continueOnError＝true|false 有了错误是否继续运行

定义数据库驱动信息

/src/main/resources/application.yml

logging:
  level:
    org.springframework: INFO
    com.example: DEBUG
################### DataSource Configuration ##########################
spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/gs-jdbc
    username: root
    password:
    initialize: true
init-db: true

其中

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/gs-jdbc
    username: root
    password:

我是用的mysql,你也可以定义其它或者不定义，如果不定义，springBoot会自动为我们配置一个嵌入的数据库( Embedded database)

自定义数据源

如果你不想用默认的配置数据源，如你想用阿里巴巴的数据池管理数据源，你也可以自己配置

先排除tomcat-jdbc的默认配置dataSource

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jdbc</artifactId>
        </exclusion>
    </exclusions>
</dependency>

定义自己的数据资源 这里使用了阿里巴巴的数据池管理,你也可以使用BasicDataSource

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.0.19</version>
</dependency>

/src/main/java/com/example/SpringBootJdbcDemoApplication.java

package com.example;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;

import javax.sql.DataSource;

/**
 * Created by tom on 2016/5/21.
 */
@SpringBootApplication
public class SpringBootJdbcDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringBootJdbcDemoApplication.class, args);
    }

    @Autowired
    private Environment env;

    @Bean
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(env.getProperty("spring.datasource.url"));
        dataSource.setUsername(env.getProperty("spring.datasource.username"));//用户名
        dataSource.setPassword(env.getProperty("spring.datasource.password"));//密码
        dataSource.setInitialSize(2);
        dataSource.setMaxActive(20);
        dataSource.setMinIdle(0);
        dataSource.setMaxWait(60000);
        dataSource.setValidationQuery("SELECT 1");
        dataSource.setTestOnBorrow(false);
        dataSource.setTestWhileIdle(true);
        dataSource.setPoolPreparedStatements(false);
        return dataSource;
    }
}

你也可以用别的：

<dependency>
    <groupId>commons-dbcp</groupId>
    <artifactId>commons-dbcp</artifactId>
    <version>1.4</version>
</dependency>

    @Bean
    public DataSource dataSource() {
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
        dataSource.setUrl(env.getProperty("spring.datasource.url"));
        dataSource.setUsername(env.getProperty("spring.datasource.username"));
        dataSource.setPassword(env.getProperty("spring.datasource.password"));
        return dataSource;
    }

创建实体对象

/src/main/java/com/example/domain/User.java

package com.example.domain;

/**
 * Created by tom on 2016/5/21.
 */
public class User
{
    private Integer id;
    private String name;
    private String email;

    public User()
    {
    }

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

    public Integer getId()
    {
        return id;
    }

    public void setId(Integer id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public String getEmail()
    {
        return email;
    }

    public void setEmail(String email)
    {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

创建持久层

有了上面的数据源配置，我们可以注入JdbcTemplate到数据访问组件并与数据库交互。 /src/main/java/com/example/repositories/UserRepository.java

package com.example.repositories;

import com.example.domain.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.PreparedStatementCreator;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import java.sql.*;
import java.util.List;

/**
 * Created by tom on 2016/5/21.
 */
@Repository
public class UserRepository {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Transactional(readOnly = true)
    public List<User> findAll() {
        return jdbcTemplate.query("select * from users", new UserRowMapper());
    }

    @Transactional(readOnly = true)
    public User findUserById(int id) {
        return jdbcTemplate.queryForObject("select * from users where id=?", new Object[]{id}, new UserRowMapper());
    }

    public User create(final User user) {
        final String sql = "insert into users(name,email) values(?,?)";

        KeyHolder holder = 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, user.getName());
                ps.setString(2, user.getEmail());
                return ps;
            }
        }, holder);

        int newUserId = holder.getKey().intValue();
        user.setId(newUserId);
        return user;
    }

    public void delete(final Integer id) {
        final String sql = "delete from users where id=?";
        jdbcTemplate.update(sql,
                new Object[]{id},
                new int[]{java.sql.Types.INTEGER});
    }

    public void update(final User user) {
        jdbcTemplate.update(
                "update users set name=?,email=? where id=?",
                new Object[]{user.getName(), user.getEmail(), user.getId()});
    }
}

class UserRowMapper implements RowMapper<User> {

    @Override
    public User mapRow(ResultSet rs, int rowNum) throws SQLException {
        User user = new User();
        user.setId(rs.getInt("id"));
        user.setName(rs.getString("name"));
        user.setEmail(rs.getString("email"));

        return user;
    }

}

你或许己注意到，大多数时候，我们都在应用中做这些配置的事。

创建单元测试测试我们的持久层方法

/src/test/java/SpringBootJdbcDemoApplicationTests.java

import com.example.SpringBootJdbcDemoApplication;
import com.example.domain.User;
import com.example.repositories.UserRepository;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.List;

import static org.junit.Assert.*;
import static org.junit.Assert.assertEquals;

/**
 * Created by tom on 2016/5/21.
 */
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(SpringBootJdbcDemoApplication.class)
public class SpringBootJdbcDemoApplicationTests
{
     Logger logger= LoggerFactory.getLogger(SpringBootJdbcDemoApplicationTests.class);
    @Autowired
    private UserRepository userRepository;

    @Test public void testAll(){
        findAllUsers();
        findUserById();
        createUser();
    }

    @Test
    public void findAllUsers()  {
        List<User> users = userRepository.findAll();
        assertNotNull(users);
        assertTrue(!users.isEmpty());

    }

    @Test
    public void findUserById()  {
        User user = userRepository.findUserById(1);
        assertNotNull(user);
    }
    private void updateById(Integer id)  {
        User newUser = new User(id, "JackChen", "[e-mail]");
        userRepository.update(newUser);
        User newUser2 = userRepository.findUserById(newUser.getId());
        assertEquals(newUser.getName(), newUser2.getName());
        assertEquals(newUser.getEmail(), newUser2.getEmail());
    }
    @Test
    public void createUser() {
        User user = new User(0, "tom", "[e-mail]");
        User savedUser = userRepository.create(user);
        logger.debug("{}",savedUser);
        User newUser = userRepository.findUserById(savedUser.getId());
        assertEquals("tom", newUser.getName());
        assertEquals("[e-mail]", newUser.getEmail());
        updateById(newUser.getId());
        userRepository.delete(newUser.getId());
    }
}

源代码请访问： https://github.com/tomlxq/best-practice/tree/master/gs-jdbc