1、JdbcTemplate操作数据库
Spring对数据库的操作在jdbc上面做了深层次的封装,使用spring的注入功能,可以把DataSource注册到 JdbcTemplate之中。同时,为了支持对properties文件的支持,spring提供了类似于EL表达式的方式,把 dataSource.properties的文件参数引入到参数配置之中,<context:property-placeholder location="classpath:jdbc.properties" />。
实例代码如下:
提供数据源的相关配置信息:jdbc.properties
- driverClassName=org.gjt.mm.mysql.Driver
- url=jdbc\:mysql\://localhost\:3306/stanley?useUnicode\=true&characterEncoding\=UTF-8
- username=root
- password=123456
- initialSize=1
- maxActive=500
- maxIdle=2
- minIdle=1
提供spring的配置文件,将jdbc.properties与JdbcTemplate粘合起来的配置文件:beans.xml
- <?xml version= "1.0" encoding= "UTF-8" ?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xmlns:context="http://www.springframework.org/schema/context"
- xmlns:aop="http://www.springframework.org/schema/aop"
- xmlns:tx="http://www.springframework.org/schema/tx"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
- http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
- http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
- http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
- <context:property-placeholder location="classpath:jdbc.properties" />
- <bean id="dataSource" class = "org.apache.commons.dbcp.BasicDataSource" destroy-method= "close" >
- <property name="driverClassName" value= "${driverClassName}" />
- <property name="url" value= "${url}" />
- <property name="username" value= "${username}" />
- <property name="password" value= "${password}" />
- <!-- 连接池启动时的初始值 -->
- <property name="initialSize" value= "${initialSize}" />
- <!-- 连接池的最大值 -->
- <property name="maxActive" value= "${maxActive}" />
- <!-- 最大空闲值.当经过一个高峰时间后,连接池可以慢慢将已经用不到的连接慢慢释放一部分,一直减少到maxIdle为止 -->
- <property name="maxIdle" value= "${maxIdle}" />
- <!-- 最小空闲值.当空闲的连接数少于阀值时,连接池就会预申请去一些连接,以免洪峰来时来不及申请 -->
- <property name="minIdle" value= "${minIdle}" />
- </bean>
- <bean id="txManager" class = "org.springframework.jdbc.datasource.DataSourceTransactionManager" >
- <property name="dataSource" ref= "dataSource" />
- </bean>
- <aop:config>
- <aop:pointcut id="transactionPointcut" expression= "execution(* cn.comp.service..*.*(..))" />
- <aop:advisor advice-ref="txAdvice" pointcut-ref= "transactionPointcut" />
- </aop:config>
- <tx:advice id="txAdvice" transaction-manager= "txManager" >
- <tx:attributes>
- <tx:method name="get*" read-only= "true" propagation= "NOT_SUPPORTED" />
- <tx:method name="*" />
- </tx:attributes>
- </tx:advice>
- <bean id="personService" class = "cn.comp.service.impl.PersonServiceBean" >
- <property name="dataSource" ref= "dataSource" />
- </bean>
- </beans>
或者使用获取jdbc相关连接
- <bean name= "dataSource" class = "org.springframework.jdbc.datasource.DriverManagerDataSource" >
- <property name="driverClassName" value= "com.mysql.jdbc.Driver" ></property>
- <property name="url" value= "jdbc:mysql://localhost/dbunit" ></property>
- <property name="password" value= "root" />
- <property name="username" value= "root" />
- </bean>
提供POJO的java类:Person.java
- public class Person {
- private Integer id;
- private String name;
- public Person(){}
- public Person(String name) {
- this .name = name;
- }
- public Integer getId() {
- return id;
- }
- public void setId(Integer id) {
- this .id = id;
- }
- public String getName() {
- return name;
- }
- public void setName(String name) {
- this .name = name;
- }
- }
提供对Person的操作接口:PersonService.java
- public interface PersonService {
- /**
- * 保存person
- * @param person
- */
- public void save(Person person);
- /**
- * 更新person
- * @param person
- */
- public void update(Person person);
- /**
- * 获取person
- * @param personid
- * @return
- */
- public Person getPerson(Integer personid);
- /**
- * 获取所有person
- * @return
- */
- public List<Person> getPersons();
- /**
- * 删除指定id的person
- * @param personid
- */
- public void delete(Integer personid) throws Exception;
- }
提供对接口的实现类:PersonServiceBean.java
- public class PersonServiceBean implements PersonService {
- private JdbcTemplate jdbcTemplate;
- public void setDataSource(DataSource dataSource) {
- this .jdbcTemplate = new JdbcTemplate(dataSource);
- }
- public void delete(Integer personid) throws Exception{
- jdbcTemplate.update("delete from person where id=?" , new Object[]{personid},
- new int []{java.sql.Types.INTEGER});
- }
- public Person getPerson(Integer personid) {
- return (Person)jdbcTemplate.queryForObject( "select * from person where id=?" , new Object[]{personid},
- new int []{java.sql.Types.INTEGER}, new PersonRowMapper());
- }
- @SuppressWarnings ( "unchecked" )
- public List<Person> getPersons() {
- return (List<Person>)jdbcTemplate.query( "select * from person" , new PersonRowMapper());
- }
- public void save(Person person) {
- jdbcTemplate.update("insert into person(name) values(?)" , new Object[]{person.getName()},
- new int []{java.sql.Types.VARCHAR});
- }
- public void update(Person person) {
- jdbcTemplate.update("update person set name=? where id=?" , new Object[]{person.getName(), person.getId()},
- new int []{java.sql.Types.VARCHAR, java.sql.Types.INTEGER});
- }
- }
提供在查询对象时,记录的映射回调类:PersonRowMapper.java
- public class PersonRowMapper implements RowMapper {
- public Object mapRow(ResultSet rs, int index) throws SQLException {
- Person person = new Person(rs.getString( "name" ));
- person.setId(rs.getInt("id" ));
- return person;
- }
- }
【注意】:由于dbcp的jar包对common-pool和commons-collections的jar包有依赖,所有需要把他们一起引入 到工程中。【 commons-dbcp-1.2.1.jar, commons-pool-1.2.jar, commons-collections-3.1.jar】, 参考文档《JDBC高级部分》:http://tianya23.blog.51cto.com/1081650/270849
2、JdbcTemplate事务
事务的操作首先要通过配置文件,取得spring的支持, 再在java程序中显示的使用@Transactional注解来使用事务操作。
在xml配置文件中增加对事务的支持:
- <bean id= "txManager" class = "org.springframework.jdbc.datasource.DataSourceTransactionManager" >
- <property name="dataSource" ref= "dataSource" />
- </bean>
- <tx:annotation-driven transaction-manager="txManager" />
- <bean id="personService" class = "cn.comp.service.impl.PersonServiceBean" >
- <property name="dataSource" ref= "dataSource" />
- </bean>
在java程序中显示的指明是否需要事务,当出现运行期异常Exception或一般的异常Exception是否需要回滚
- @Transactional
- public class PersonServiceBean implements PersonService {
- private JdbcTemplate jdbcTemplate;
- public void setDataSource(DataSource dataSource) {
- this .jdbcTemplate = new JdbcTemplate(dataSource);
- }
- // unchecked ,
- // checked
- @Transactional (noRollbackFor=RuntimeException. class )
- public void delete(Integer personid) throws Exception{
- jdbcTemplate.update("delete from person where id=?" , new Object[]{personid},
- new int []{java.sql.Types.INTEGER});
- throw new RuntimeException( "运行期例外" );
- }
- @Transactional (propagation=Propagation.NOT_SUPPORTED)
- public Person getPerson(Integer personid) {
- return (Person)jdbcTemplate.queryForObject( "select * from person where id=?" , new Object[]{personid},
- new int []{java.sql.Types.INTEGER}, new PersonRowMapper());
- }
- @Transactional (propagation=Propagation.NOT_SUPPORTED)
- @SuppressWarnings ( "unchecked" )
- public List<Person> getPersons() {
- return (List<Person>)jdbcTemplate.query( "select * from person" , new PersonRowMapper());
- }
- public void save(Person person) {
- jdbcTemplate.update("insert into person(name) values(?)" , new Object[]{person.getName()},
- new int []{java.sql.Types.VARCHAR});
- }
- public void update(Person person) {
- jdbcTemplate.update("update person set name=? where id=?" , new Object[]{person.getName(), person.getId()},
- new int []{java.sql.Types.VARCHAR, java.sql.Types.INTEGER});
- }
- }
在默认情况下,Spring会对RuntimeException异常进行回滚操作,而对Exception异常不进行回滚。可以显示的什么什么 样的异常需要回滚,什么样的异常不需要回滚, 通过 @Transactional(noRollbackFor=RuntimeException.class)设置要求运行时异常不回滚 或者通过RollbackFor=Exception.class来要求需要捕获的异常回滚。
【注意】Spring对数据库的操作提供了强大的功能,比如RowMapper接口封装数据库字段与Java属性的映射、查询返回List的函数 等,但是里面还要写一堆SQL语句还是比较烦人的,在这部分建议使用ibatis或hibernate来代替, 不知道Spring后期的版本会不会把这个整合到里面。
- <dependency>
- <groupId>com.alibaba.external</groupId>
- <artifactId>sourceforge.spring</artifactId>
- <version>2.5 . 6 </version>
- </dependency>
- <dependency>
- <groupId>com.alibaba.external</groupId>
- <artifactId>jdbc.mysql.mysql-connector</artifactId>
- <version>5.1 . 6 </version>
- </dependency>
- <dependency>
- <groupId>com.alibaba.external</groupId>
- <artifactId>jakarta.commons.dbcp</artifactId>
- <version>1.4 </version>
- </dependency>
参考文章:http://xiao1227372602.iteye.com/blog/1631268