Spring boot 与 JdbcTemplate 一起工作

原文：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", "JackChen@qq.com"); 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", "tom@gmail.com"); User savedUser = userRepository.create(user); logger.debug("{}",savedUser); User newUser = userRepository.findUserById(savedUser.getId()); assertEquals("tom", newUser.getName()); assertEquals("tom@gmail.com", 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