Spring--JdbcTemplate详解-1

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