spring boot整合mybatis使用c3p0数据源连接mysql

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.4.1.RELEASE</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <version>1.4.1.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
      <version>1.4.1.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>1.1.1</version>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.33</version>
    </dependency>
    <dependency>
      <groupId>c3p0</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.1.2</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan(value="com.myk.spring.t3")//扫描mapper包
@EnableAutoConfiguration//自动载入应用程序所需的所有Bean，当使用Exclude这个属性时，是禁止自动配置某个类
public class Application {
  public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
  }
}

datasource: 
 url: jdbc:mysql://ip:port/databaseName
 driver-class: com.mysql.jdbc.Driver
 username: ***
 password: ***

import javax.sql.DataSource;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import com.mchange.v2.c3p0.ComboPooledDataSource;

@Configuration
public class DataSourceConfig {

  @Bean(name="dataSource")
  @Qualifier(value="dataSource")//限定描述符除了能根据名字进行注入，但能进行更细粒度的控制如何选择候选者
  @Primary//用@Primary区分主数据源
  @ConfigurationProperties(prefix="c3p0.primary")//指定配置文件中，前缀为c3p0的属性值
  public DataSource dataSource(){
    return DataSourceBuilder.create().type(ComboPooledDataSource.class).build();//创建数据源
  }
  /**
  *返回sqlSessionFactory
  */
  @Bean
  public SqlSessionFactoryBean sqlSessionFactoryBean(){
    SqlSessionFactoryBean sqlSessionFactory = new SqlSessionFactoryBean();
    sqlSessionFactory.setDataSource(dataSource());
    return sqlSessionFactory;
  }
}

import java.util.List;

public interface ExamPleMapper {
  public List<Users> getUsers();
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.*.ExamPleMapper">
  <select id="getUsers" resultType="com.*.Users">
    select * from users
  </select>
</mapper>

public class Users {
  private int userid;
  private String username;

  @Override
  public String toString() {
    return "Users [userid=" + userid + ", username=" + username + "]";
  }

  public int getUserid() {
    return userid;
  }

  public void setUserid(int userid) {
    this.userid = userid;
  }

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public Users(int userid, String username) {
    super();
    this.userid = userid;
    this.username = username;
  }

  public Users() {
    super();
    // TODO Auto-generated constructor stub
  }

}

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping(value="/example2")//映射
public class Example2 {
  @Autowired
  public ExamPleMapper examPleMapper;

  @ResponseBody
  @RequestMapping(value="/gu")
  public List<Users> getUsers(){
    return examPleMapper.getUsers();
  }
}