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JdbcTemplate利用教程详解

时候:2012-10-23 00:08来源:知行网www.zhixing123.cn 编辑:麦田守望者

1、JdbcTemplate操纵数据库

Spring对数据库的操纵在jdbc下面做了深层次的封装,利用spring的注入服从,可以把DataSource注册到JdbcTemplate当中。同时,为了支撑对properties文件的支撑,spring供应了近似于EL表达式的体例,把dataSource.properties的文件参数引入到参数建设当中,<context:property-placeholder location="classpath:jdbc.properties" />。

 
实例代码以下:
供应数据源的相关建设信息: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
 

 
供应spring的建设文件,将jdbc.properties与JdbcTemplate粘合起来的建设文件: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="${initialSize}"/>
<!-- 连接池的最年夜值 -->
<property name="maxActive" value="${maxActive}"/>
<!-- 最年夜余暇值.当颠末一个岑岭时候后,连接池可以渐渐将已用不到的连接渐渐开释一部分,一向减少到maxIdle为止 -->
<property name="maxIdle" value="${maxIdle}"/>
<!-- 最小余暇值.当余暇的连接数少于阀值时,连接池就会预请求去一些连接,以避免洪峰来时来不及请求 -->
<property name="minIdle" value="${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>

 
供应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;
}
}

 
供应对Person的操纵接口: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);
/**
* 获得person
* @param personid
* @return
*/

public Person getPerson(Integer personid);
/**
* 获得所有person
* @return
*/

public List<Person> getPersons();
/**
* 删除指定id的person
* @param personid
*/

public void delete(Integer personid) throws Exception;
}
 

 
供应对接口的实现类: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});
}
}

 
供应在查询工具时,记录的映照回调类: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;
}
}
 

 
【重视】:因为dbcp的jar包对common-pool和commons-collections的jar包有依靠,所有需求把他们一路引入到工程中。【 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事件
事件的操纵起首要经由过程建设文件,获得spring的支撑, 再在java法度中显现的利用@Transactional注解来利用事件操纵。

 
在xml建设文件中增加对事件的支撑:
<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法度中显现的指明是不是需求事件,当呈现运行期异常Exception或一般的异常Exception是不是需求回滚
@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});
}
}
在默许环境下,Spring会对RuntimeException异常进行回滚操纵,而对Exception异常不进行回滚。可以显现的甚么甚么样的异常需求回滚,甚么样的异常不需求回滚, 经由过程 @Transactional(noRollbackFor=RuntimeException.class)设置请求运行时异常不回滚 或经由过程RollbackFor=Exception.class来请求需求捕获的异常回滚。

 
【重视】Spring对数据库的操纵供应了强年夜的服从,比如RowMapper接口封装数据库字段与Java属性的映照、查询前往List的函数等,但是内里还要写一堆SQL语句还是比较烦人的,在这部分建议利用ibatis或hibernate来代替, 不晓得Spring后期的版本会不会把这个整合到内里。
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