Spring JdbcTemplate的配置使用

需要的jar包支持-

c3p0-0.9.2.1.jar、mchange-commons-java-0.2.3.4.jar

1.jdbc.properties文件

jdbc.mysql.className=com.mysql.cj.jdbc.Driver
jdbc.mysql.url=jdbc:mysql://localhost:3306/company?serverTimezone=GMT%2B8
jdbc.mysql.user=root
jdbc.mysql.password=l12345

2.在spring.xml配置中获取数据源资源文件(方法对web.xml引入.properties文件无效。) 1)以下方法只能在一个.xml处引入.properties文件，其他地方再引入将报错

2)(本条转载自https://blog.csdn.net/miaomiaosky/article/details/81567676)

         

        
            
                classpath:lts-client.properties
            
        

本方法可用于在多处.xml文件引入.properties文件
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原文链接：https://blog.csdn.net/miaomiaosky/article/details/81567676

3.配置c3p0的连接参数（需要c3p0的jar）

4.配置JdbcTemplate的Bean

id记得加，否则会报以下错

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'empController': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'empService': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'empDao': Unsatisfied dependency expressed through field 'jt'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.jdbc.core.JdbcTemplate' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=jdbcTemplate)}

数据源已经配置好

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5.注入使用jdbc

    //byName
    @Resource
    private JdbcTemplate jt;

    public User getByUsername(String username) {
        //创建sql语句
        String sql = "select * from user where username = ?";
        //通过jbbc模板的方法，对数据库进行操作。
        return jt.queryForObject(sql,new BeanPropertyRowMapper<>(User.class),username);
    }