spring boot获取datasource为null_Spring讲解九

Spring JDBC 数据访问

Spring JDBC是Spring所提供的持久层技术,它的主要目标是降低使用JDBC API的门槛,以一种更直接,更简介,更简单的方式使用JDBC API, 在Spring JDBC里,仅需做那些与业务相关的DML操作,而将资源获取,Statment创建,资源释放以及异常处理等繁杂而乏味的工作交给Spring JDBC.
虽然ORM的框架已经成熟丰富,但是JDBC的灵活,直接的特性,依然让他拥有自己的用武之地,如在完全依赖查询模型动态产生查询语句的综合查询系统中,Hibernaye,MyBatis,JPA等框架都无法使用,这里JDBC是唯一的选择.

主要内容:学习使用JdbcTemplate API和 如何使用Spring管理 JdbcTemplate

1. JdbcTemplate入门

1.1 创建项目

• 项目名: spring-jdbc
• 引入jar包
  <dependencies>
  <dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>3.8.1</version>
  <scope>test</scope>
  </dependency>
  ​
  <dependency>
  <groupId>aopalliance</groupId>
  <artifactId>aopalliance</artifactId>
  <version>1.0</version>
  </dependency>
  ​
  <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
  <dependency>
  <groupId>org.aspectj</groupId>
  <artifactId>aspectjweaver</artifactId>
  <version>1.8.10</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-aspects</artifactId>
  <version>4.3.7.RELEASE</version>
  </dependency>
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-aop</artifactId>
  <version>4.3.10.RELEASE</version>
  </dependency>
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context-support</artifactId>
  <version>4.3.11.RELEASE</version>
  </dependency>
  ​
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>4.3.10.RELEASE</version>
  </dependency>
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-core</artifactId>
  <version>4.3.10.RELEASE</version>
  </dependency>
  ​
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-beans</artifactId>
  <version>4.3.10.RELEASE</version>
  </dependency>
  ​
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-expression</artifactId>
  <version>4.3.10.RELEASE</version>
  </dependency>
  ​
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-jdbc</artifactId>
  <version>4.3.9.RELEASE</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
  <dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.38</version>
  </dependency>
  <dependency>
  <groupId>commons-logging</groupId>
  <artifactId>commons-logging</artifactId>
  <version>1.1.2</version>
  </dependency>
  ​
  <dependency>
  <groupId>log4j</groupId>
  <artifactId>log4j</artifactId>
  <version>1.2.14</version>
  </dependency>
  ​
  <dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.38</version>
  </dependency>
  ​
  <!-- https://mvnrepository.com/artifact/commons-dbcp/commons-dbcp -->
  <dependency>
  <groupId>commons-dbcp</groupId>
  <artifactId>commons-dbcp</artifactId>
  <version>1.4</version>
  </dependency>
  ​
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-test</artifactId>
  <version>4.3.10.RELEASE</version>
  <scope>test</scope>
  </dependency>
  ​
  <!-- https://mvnrepository.com/artifact/com.mchange/mchange-commons-java -->
  <dependency>
  <groupId>com.mchange</groupId>
  <artifactId>mchange-commons-java</artifactId>
  <version>0.2.11</version>
  </dependency>
  ​
  <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot -->
  <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot</artifactId>
  <version>1.5.7.RELEASE</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 -->
  <dependency>
  <groupId>com.mchange</groupId>
  <artifactId>c3p0</artifactId>
  <version>0.9.5.2</version>
  </dependency>
  <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-tx</artifactId>
  <version>4.3.9.RELEASE</version>
  </dependency>

• 导入日志:log4j.properties

1.2 创建数据库

数据库名: springjdbc

创建角色表:

CREATE TABLE `role` (
  `rid` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '角色id',
  `rname` VARCHAR(20) NOT NULL COMMENT '角色名',
  `alias` VARCHAR(20) NOT NULL COMMENT '角色别名',
  PRIMARY KEY (`rid`)
)
​
INSERT INTO role (rid,rname,alias)
    VALUES(1,'admin','系统管理员'),(2,'dispatcher','调度员');

1.3 测试代码

 @Test
 public  void test1() throws Exception {
    
        //TODO 测试jdbcTemplate简单使用
        //1.创建c3p0链接池
        ComboPooledDataSource dataSource  = new ComboPooledDataSource();
        dataSource.setDriverClass("com.mysql.jdbc.Driver");
        dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/springjdbc");
        dataSource.setUser("root");
        dataSource.setPassword("111");
​
​
        //创建jdbcTemplate对象
        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
​
        //创建sql语句
        String sq