前言:
前面有讲过 Spring IOC以及AOP的基本使用方法, 这里就再来讲下Spring JDBCTemplate的使用方法.
一, 概述
这里先说一下Spring 整合的一些模板:
从上图中可以看出 Spring为各种支持的持久化技术，都提供了简单操作的模板和回调.
二, 使用JdbcTemplate
2.1 Spring JDBC是Spring提供的持久层技术
简化JDBC API开发，使用上和Apache公司的DBUtils框架非常类似
具体开发使用的jar包结构如图:
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2.2, Spring配置连接池
1, 配置Spring的内置的连接池
1 <!-- 配置Spring的内置的连接池 --> 2 <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 3 <property name="driverClassName" value="com.mysql.jdbc.Driver"/> 4 <property name="url" value="jdbc:mysql:///spring_day02"/> 5 <property name="username" value="root"/> 6 <property name="password" value="123"/> 7 </bean>
2, 配置DBCP连接池
1 <!-- 配置DBCP连接池 --> 2 <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"> 3 <property name="driverClassName" value="com.mysql.jdbc.Driver"/> 4 <property name="url" value="jdbc:mysql:///spring_day02"/> 5 <property name="username" value="root"/> 6 <property name="password" value="123"/> 7 </bean>
注: 这里如果使用DBCP连接池的话还需要导入Spring 整合DBCP的两个jar包.
3. C3P0连接池
1 <!-- 配置C3P0连接池 --> 2 <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> 3 <property name="driverClass" value="com.mysql.jdbc.Driver"/> 4 <property name="jdbcUrl" value="jdbc:mysql:///spring_day02"/> 5 <property name="user" value="root"/> 6 <property name="password" value="123"/> 7 </bean>
4,引入属性文件: 写jdbc.properties 文件, 然后直接将配置文件注入到Spring中
jdbc.properties 配置文件:
jdbc.driverClass=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql:///spring_day02 jdbc.user=root jdbc.password=123
在Spring的核心配置中引入属性文件: 两种 方式
1 <!-- 引入方式一:引入属性文件 --> 2 <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> 3 <property name="location" value="classpath:jdbc.properties"/> 4 </bean> 5 <!--引入方式二:引入context的约束--> 6 <context:property-placeholder location="classpath:jdbc.properties"/>
三, 开发案例, 使用Spring JDBCTemplate 进行CRUD操作.
Customer.java:
1 public class Customer {
2 private Integer cid;
3 private String cname;
4 private Integer age;
5 public Integer getCid() {
6 return cid;
7 }
8 public void setCid(Integer cid) {
9 this.cid = cid;
10 }
11 public String getCname() {
12 return cname;
13 }
14 public void setCname(String cname) {
15 this.cname = cname;
16 }
17 public Integer getAge() {
18 return age;
19 }
20 public void setAge(Integer age) {
21 this.age = age;
22 }
23 @Override
24 public String toString() {
25 return "Customer [cid=" + cid + ", cname=" + cname + ", age=" + age
26 + "]";
27 }
28
29 }
CustomerDao.java:
1 /**
2 * 完成对Customer的CRUD的操作
3 *
4 */
5 public class CustomerDao extends JdbcDaoSupport {
12
13 public void save(Customer customer) {
14 this.getJdbcTemplate().update("insert into customer values (null,?,?)",
15 customer.getCname(), customer.getAge());
16 }
17
18 public void update(Customer customer) {
19 this.getJdbcTemplate().update(
20 "update customer set cname = ?,age = ? where cid = ?",
21 customer.getCname(), customer.getAge(), customer.getCid());
22 }
23
24 public void delete(Integer cid) {
25 this.getJdbcTemplate()
26 .update("delete from customer where cid = ?", cid);
27 }
28
29 public Integer findCount() {
30 int count = this.getJdbcTemplate().queryForInt(
31 "select count(*) from customer");
32 return count;
33 }
34
35 public String findNameById(Integer cid) {
36 String cname = this.getJdbcTemplate().queryForObject(
37 "select cname from customer where cid = ?", String.class, cid);
38 return cname;
39 }
40
41 public Customer findById(Integer cid) {
42 Customer customer = this.getJdbcTemplate().queryForObject(
43 "select * from customer where cid = ?",
44 new BeanPropertyRowMapper<Customer>(Customer.class), cid);
45 return customer;
46 }
47
48 public List<Customer> findAll() {
49 List<Customer> list = this.getJdbcTemplate().query("select * from customer",
50 new BeanPropertyRowMapper<Customer>(Customer.class));
51 return list;
52 }
53 }
SpringDemo2.java 测试类:
1 @RunWith(SpringJUnit4ClassRunner.class)
2 @ContextConfiguration("classpath:applicationContext2.xml")
3 public class SpringDemo2 {
4
5 @Resource(name="customerDao")
6 private CustomerDao customerDao;
7
8 @Test
9 public void demo1(){
10
11 Customer customer = new Customer();
12 customer.setCname("马大帅");
13 customer.setAge(48);
14
15 customerDao.save(customer);
16 }
17
18 @Test
19 public void demo2(){
20
21 Customer customer = new Customer();
22 customer.setCid(8);
23 customer.setCname("马小帅");
24 customer.setAge(38);
25
26 customerDao.update(customer);
27 }
28
29 @Test
30 public void demo3(){
31 customerDao.delete(7);
32 }
33
34 @Test
35 public void demo4(){
36 int count = customerDao.findCount();
37 System.out.println(count);
38 }
39
40 @Test
41 public void demo5(){
42 String cname = customerDao.findNameById(8);
43 System.out.println(cname);
44 }
45
46 @Test
47 public void demo6(){
48 Customer customer = customerDao.findById(8);
49 System.out.println(customer);
50 }
51
52 @Test
53 public void demo7(){
54 List<Customer> customers = customerDao.findAll();
55 for (Customer customer : customers) {
56 System.out.println(customer);
57 }
58 }
59 }
applicationContext.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="
6 http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
7 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
8
9
10 <context:property-placeholder location="classpath:jdbc.properties"/>
11
12 <!-- 配置C3P0连接池 -->
13 <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
14 <property name="driverClass" value="${jdbc.driverClass}"/>
15 <property name="jdbcUrl" value="${jdbc.url}"/>
16 <property name="user" value="${jdbc.user}"/>
17 <property name="password" value="${jdbc.password}"/>
18 </bean>
19
20
21 <!-- 配置DAO -->
22 <bean id="customerDao" class="cn.itcast.jdbc.demo2.CustomerDao">
23 <property name="dataSource" ref="dataSource"/>
24 </bean>
25 </beans>
好了, 一个基本的CRUD操作就完成了, 在这里我们可以发现配置文件特别的简洁, 我们只是给customerDao注入了一个dataSource , 然后在CustomerDao.java中就可以用this.getJdbcTemplate()获取到JDBCTemplate的实例了, 这个原理是因为我们的CustomerDao继承了 JdbcDaoSupport , 这里我们就来看下它的源码:
首先我们使用this.getJdbcTemplate而获取到一个jdbcTemplate实例:
1 /**
2 * Return the JdbcTemplate for this DAO,
3 * pre-initialized with the DataSource or set explicitly.
4 */
5 public final JdbcTemplate getJdbcTemplate() {
6 return this.jdbcTemplate;
7 }
那么又返回的这个this.jdbcTemplate是否是有值得呢? 再看源代码原来是在我们setDataSource的时候生成了jdbcTemplate实例.
1 /**
2 * Set the JDBC DataSource to be used by this DAO.
3 */
4 public final void setDataSource(DataSource dataSource) {
5 if (this.jdbcTemplate == null || dataSource != this.jdbcTemplate.getDataSource()) {
6 this.jdbcTemplate = createJdbcTemplate(dataSource);
7 initTemplateConfig();
8 }
9 }
