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 >
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 { public void save(Person person); public void update(Person person); public Person getPerson(Integer personid); public List<Person> getPersons(); 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》：
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}); } }
【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。