Cannot find class [com.alibaba.druid.pool.DruidDataSuorce]
八月 06, 2020 3:52:33 下午 org.springframework.context.support.AbstractApplicationContext refresh
警告: Exception encountered during context initialization - cancelling refresh attempt:
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'bookService': Unsatisfied dependency expressed through field 'bookDao';
nested exception is org.springframework.beans.factory.CannotLoadBeanClassException:
Cannot find class [com.alibaba.druid.pool.DruidDataSuorce] for bean with name 'DataSource' defined in class path resource [Beans1.xml];
nested exception is java.lang.ClassNotFoundException: com.alibaba.druid.pool.DruidDataSuorce
(这是我在自学spring整合JdbcTemplate时，运行了一个例子出现的错误，花了两天才解决，仅供参考)
1、出现这种错误首先你要去检查你有没有导入druid的jar包
阿里巴巴druid.jar包下载地址：https://mvnrepository.com/artifact/com.alibaba/druid
2、如果jar包导入没问题，你先去查看你的MySQL版本是不是5+的
如果版本是5的话你应该导入和版本一致的mysql-connector的jar包，例如：mysql-connector-java-5.1.39-bin.jar
而如果你的MySQL版本是5+新版本的话那你就要导入新版本的mysql-connector的jar包，例如：mysql-connector-java-8.0.19.jar
3、如果还是没用的话，那你就要去检查你的spring配置了（也就是xml文件），比如你的配置中有某段代码是复制粘贴过来的，那你最好自己重新敲一遍，复制粘贴有可能会导致空格出错，不懂的话可以看下我下面的这个小例子（我就是因为这个原因，搞了两天才搞出来 =_=......）
mysql8.0新版本如何配置连接池（一个简单的JdbcTemplate小例子来说明）
（1）引入jar包，这些jar包有一部分要用到（在这个例子）
（2）打开数据库（我这里的数据库是spring_jdbctemplate_demo1,其中有一个表teacher）
（3）创建这些类、xml和外部属性文件
创建BookService类
1 @Service //使用注解方式创建对象 2 public class BookService { 3 4 //注入dao 5 @Autowired //注解注入属性 6 private BookDao bookDao; 7 8 //插入方法 9 public void addTeacher(Teacher teacher) { 10 bookDao.add(teacher); 11 } 12 13 //修改方法 14 public void update(Teacher teacher) { 15 bookDao.update(teacher); 16 } 17 18 //删除方法 19 public void delete(String name) { 20 bookDao.delete(name); 21 } 22 23 //查询行数方法 24 public void selectCountAll() { 25 bookDao.selectCount(); 26 } 27 28 //查询返回对象 29 public Teacher selectObject(String name) { 30 return bookDao.selectReturnObject(name); 31 } 32 33 //查询返回集合 34 public List<Teacher> selectList() { 35 return bookDao.selectReturnList(); 36 } 37 38 //批量添加方法 39 public void batchAdd(List<Object[]> batchAddRow) { 40 bookDao.batchAddTeacher(batchAddRow); 41 } 42 43 //批量修改方法 44 public void batchUpdate(List<Object[]> batchUpdateRow) { 45 bookDao.batchUpdateTeacher(batchUpdateRow); 46 } 47 48 //批量删除方法 49 public void batchDelete(List<Object[]> batchDeleteRow) { 50 bookDao.batchDeleteTeacher(batchDeleteRow); 51 } 52 }
创建BookDao接口
1 public interface BookDao { 2 3 //插入方法 4 void add(Teacher teacher); 5 6 //修改方法 7 void update(Teacher teacher); 8 9 //删除方法 10 void delete(String name); 11 12 //查询行数方法 13 void selectCount(); 14 15 //查询返回对象 16 Teacher selectReturnObject(String name); 17 18 //查询返回集合 19 List<Teacher> selectReturnList(); 20 21 //批量添加方法 22 void batchAddTeacher(List<Object[]> batchAddRow); 23 24 //批量修改方法 25 void batchUpdateTeacher(List<Object[]> batchUpdateRow); 26 27 //批量删除方法 28 void batchDeleteTeacher(List<Object[]> batchDeleteRow); 29 30 }
创建BookDaoImpl实现类
1 @Repository //使用注解方式创建对象 2 public class BookDaoImpl implements BookDao{ 3 4 //注入JdbcTemplate 5 @Autowired //注解注入属性 6 private JdbcTemplate jdbcTemplate; 7 8 //插入方法 9 @Override 10 public void add(Teacher teacher) { 11 //1、创建sql语句 12 String sql = "insert into teacher values(?,?,?)"; 13 14 //2、调用方法实现 15 Object[] array = {teacher.getID(), teacher.getName(), 16 teacher.getAddress()}; 17 int update = jdbcTemplate.update(sql, array); 18 System.out.println(update); 19 } 20 21 //修改方法 22 @Override 23 public void update(Teacher teacher) { 24 //1、创建sql语句 25 String sql = "update teacher set name=? where ID=?"; 26 27 //2、调用方法实现 28 Object[] array = { teacher.getName(), teacher.getID()}; 29 int update = jdbcTemplate.update(sql, array); 30 System.out.println(update); 31 32 } 33 34 //删除方法 35 @Override 36 public void delete(String name) { 37 //1、创建sql语句 38 String sql = "delete from teacher where name=?"; 39 40 //2、调用方法实现 41 int update = jdbcTemplate.update(sql, name); 42 System.out.println(update); 43 44 } 45 46 //查询行数方法 47 @Override 48 public void selectCount() { 49 //1、创建sql语句 50 String sql = "select COUNT(*) from teacher"; 51 52 //2、调用方法实现 53 int update = jdbcTemplate.queryForObject(sql, Integer.class); 54 System.out.println(update); 55 } 56 57 //查询返回对象 58 @Override 59 public Teacher selectReturnObject(String name) { 60 //1、创建sql语句 61 String sql = "select * from teacher where name=?"; 62 63 //2、调用方法实现 64 Teacher teacher = jdbcTemplate.queryForObject(sql, 65 new BeanPropertyRowMapper<Teacher>(Teacher.class), name); 66 return teacher; 67 } 68 69 //查询返回集合 70 @Override 71 public List<Teacher> selectReturnList() { 72 //1、创建sql语句 73 String sql = "select * from teacher"; 74 75 //2、调用方法实现 76 List<Teacher> teacherList = jdbcTemplate.query(sql, 77 new BeanPropertyRowMapper<Teacher>(Teacher.class)); 78 return teacherList; 79 } 80 81 //批量添加方法 82 @Override 83 public void batchAddTeacher(List<Object[]> batchAddRow) { 84 //1、创建sql语句 85 String sql = "insert into teacher values(?,?,?)"; 86 87 //2、调用方法实现 88 int[] array = jdbcTemplate.batchUpdate(sql, batchAddRow); 89 System.out.println(Arrays.toString(array)); 90 } 91 92 //批量修改方法 93 @Override 94 public void batchUpdateTeacher(List<Object[]> batchUpdateRow) { 95 //1、创建sql语句 96 String sql = "update teacher set name=?,address=? where ID=?"; 97 98 //2、调用方法实现 99 int[] array = jdbcTemplate.batchUpdate(sql, batchUpdateRow); 100 System.out.println(Arrays.toString(array)); 101 102 } 103 104 //批量删除方法 105 @Override 106 public void batchDeleteTeacher(List<Object[]> batchDeleteRow) { 107 //1、创建sql语句 108 String sql = "delete from teacher where ID=?"; 109 110 //2、调用方法实现 111 int[] array = jdbcTemplate.batchUpdate(sql, batchDeleteRow); 112 System.out.println(Arrays.toString(array)); 113 114 } 115 }
创建表teacher的专门类，类里面有表teacher中的全部属性以及属性对应的get或set方法
1 public class Teacher {
2
3 private String ID;
4 private String name;
5 private String address;
6
7 public String getTeacherId() {
8 return ID;
9 }
10 public void setTeacherId(String ID) {
11 this.ID = ID;
12 }
13 public String getTeacherName() {
14 return name;
15 }
16 public void setTeacherName(String name) {
17 this.name = name;
18 }
19 public String getDepartmentID() {
20 return address;
21 }
22 public void setDepartmentID(String address) {
23 this.address = address;
24 }
25 }
创建测试类
1 public class Test {
2
3 @org.junit.Test
4 public void test() {
5 ApplicationContext context =
6 new ClassPathXmlApplicationContext("Beans1.xml");
7 BookService bookService = context.getBean("bookService", BookService.class);
8 System.out.println(bookService);
9 Teacher teacher = new Teacher();
10 teacher.setTeacherId("2022");
11 teacher.setTeacherName("佳奥");
12 teacher.setDepartmentID("004");
13
14 bookService.addTeacher(teacher);
15 }
16 }
创建xml配置文件
1 <?xml version="1.0" encoding="UTF-8"?>
2 <beans xmlns="http://www.springframework.org/schema/beans"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xmlns:context="http://www.springframework.org/schema/context"
5 xsi:schemaLocation="http://www.springframework.org/schema/beans
6 http://www.springframework.org/schema/beans/spring-beans.xsd
7 http://www.springframework.org/schema/context
8 http://www.springframework.org/schema/context/spring-context.xsd">
9
10 <!-- 组件扫描 -->
11 <context:component-scan base-package="com.spring.jdbctemplate.service,
12 com.spring.jdbctemplate.dao">
13
14 </context:component-scan>
15
16
17 <!-- 引入外部属性文件 -->
18 <context:property-placeholder location="classpath:jdbc.properties"/>
19
20
21 <!-- 直接配置连接池 -->
22 <bean id="DataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
23
24 <property name="url" value="${prop.url}" />
25
26 <property name="username" value="${prop.username}" />
27
28 <property name="password" value="${prop.password}" />
29
30
31 <property name="driverClassName" value="${prop.driverClass}" />
32 </bean>
33
34
35 <!-- JdbcTemplate对象 -->
36 <bean id="jdbcTemplate1" class="org.springframework.jdbc.core.JdbcTemplate">
37
38 <!-- 注入dataSource -->
39 <property name="dataSource" ref="DataSource"></property>
40 </bean>
41
42
43 </beans>
创建一个外部属性文件，点击src（因为我是用eclipse），右键-->NEW-->Flie-->Finish，然后在文件里面写下连接连接数据库的代
连接数据库代码如下：
1 prop.driverClass = com.mysql.cj.jdbc.Driver //这个可配置也可不配置
2 prop.url = jdbc:mysql:///spring_jdbcTemplate_demo1?useSSL=false&serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
3 prop.username = *******
4 prop.password = *******
（OK，你可以去尝试了，我也是小白，希望能帮到你，加油）
