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學習筆記－Springs聲明性JDBC事務管理

近日在看臺灣人林信良的《Spring技術(shù)手冊》，這本書總體上簡單易懂，適合初學者。但是在聲明性JDBC事務管理這節(jié)中的例子程序?qū)懙牟粔蛟敿殹Ｏ聛砜纯床⒙约有薷牧讼隆?br />首先，在MySQL中建立一個表myuser。注意要讓MySQL支持事務，要選擇InnoDB類型的表。
Create table myuser（
?id int (11) not null auto_increment primary key,
name varchar(100) not null default '',
age int
）type=InnoDB;

這里有個實體類user.java:

package?onlyfun.caterpillar;

public?class?User?{

????private?Integer?id;

????private?String?name;

????private?Integer?age;

????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;

????}

????

????public?Integer?getAge()?{

????????return?age;

????}

????public?void?setAge(Integer?age)?{

????????this.age?=?age;

????}

}

為了面向接口編程，我們實現(xiàn)一個接口，讓DAO類實現(xiàn)這個接口。

package?onlyfun.caterpillar;

public?interface?IUserDAO?{

????public?void?insert(User?user);

????public?User?find(Integer?id);

}

具體的DAO類如下：在這個類中我們模擬事務處理。

package?onlyfun.caterpillar;

import?java.util.Iterator;

import?java.util.List;

import?java.util.Map;

import?javax.sql.DataSource;

import?org.springframework.jdbc.core.JdbcTemplate;

public?class?UserDAO?implements?IUserDAO?{

????private?JdbcTemplate?jdbcTemplate;

????

????public?void?setDataSource(DataSource?dataSource)?{

????????jdbcTemplate?=?new?JdbcTemplate(dataSource);

????}

????

????public?void?insert(User?user)?{//在這個方法中我們執(zhí)行了數(shù)據(jù)插入和數(shù)據(jù)查詢兩個操作，用來模擬事務操作。我們故意在查詢的語句中把數(shù)據(jù)庫表寫成smyuser。

???????????????????????????????????//這樣，在insert方法執(zhí)行過程中，會由于查詢語句出錯而撤銷之前的插入語句的效果。

???????String?name?=?user.getName();

???????int?age?=?user.getAge().intValue();

???????

???????jdbcTemplate.update("INSERT?INTO?myuser?(name,age)?"?

???????????????+?"VALUES('"?+?name?+?"',"?+?age?+?")");

???????

???????List?rows?=?jdbcTemplate.queryForList(

?????????"SELECT?*?FROM?smyuser?WHERE?id=4");

???????

???????Iterator?it?=?rows.iterator();

???????if(it.hasNext())?{

???????????Map?userMap?=?(Map)?it.next();

???????????Integer?i?=?new?Integer(userMap.get("id").toString());

???????????String?names?=?userMap.get("name").toString();

???????????Integer?ages?=?new?Integer(userMap.get("age").toString());

???????????User?users?=?new?User();

???????????

???????????users.setId(i);

???????????users.setName(name);

???????????users.setAge(age);

???????????System.out.println("names:?"?+?users.getName());

??????????

???????}

?????

????}

????public?User?find(Integer?id)?{

????????

?????????

????????List?rows?=?jdbcTemplate.queryForList(

??????????"SELECT?*?FROM?myuser?WHERE?id="?+?id.intValue());

????????

????????Iterator?it?=?rows.iterator();

????????if(it.hasNext())?{

????????????Map?userMap?=?(Map)?it.next();

????????????Integer?i?=?new?Integer(userMap.get("id").toString());

????????????String?name?=?userMap.get("name").toString();

????????????Integer?age?=?new?Integer(userMap.get("age").toString());

????????????User?user?=?new?User();

????????????

????????????user.setId(i);

????????????user.setName(name);

????????????user.setAge(age);

????????????

????????????return?user;

????????}

????????return?null;

????}

}

然后，在具體測試類中我們這樣：

package?onlyfun.caterpillar;

import?org.springframework.context.ApplicationContext;

import?org.springframework.context.

??????????????support.FileSystemXmlApplicationContext;

public?class?SpringDAODemo?{

????public?static?void?main(String[]?args)?{

????????ApplicationContext?context?=?

????????????new?FileSystemXmlApplicationContext(

????????????????????"beans-config.xml");

????????

????????User?user?=?new?User();

????????

????????user.setName("1matthew");

????????user.setAge(new?Integer(30));

????????

????????IUserDAO?userDAO?=?

????????????(IUserDAO)?context.getBean("userDAOProxy");

????????

????????userDAO.insert(user);

????????

????????user?=?userDAO.find(new?Integer(16));

????????

????????System.out.println("name:?"?+?user.getName());

????}

}

最后，我們來看配置文件：在這個文件中我們注入事務管理。

<?xml?version="1.0"?encoding="UTF-8"?>

<!DOCTYPE?beans?PUBLIC?"-//SPRING/DTD?BEAN/EN"?

??"http://www.springframework.org/dtd/spring-beans.dtd">

<beans>

????<bean?id="dataSource"?class="org.apache.commons.dbcp.BasicDataSource"?destroy-method="close">

????????<property?name="driverClassName">

????????????<value>com.mysql.jdbc.Driver</value>

????????</property>

????????<property?name="url">

????????????<value>jdbc:mysql://localhost:3306/test</value>

????????</property>

????????<property?name="username">

????????????<value>root</value>

????????</property>

????????<property?name="password">

????????????<value>131421</value>

????????</property>

????</bean>

????<bean?id="transactionManager"?class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

????????<property?name="dataSource">

????????????<ref?bean="dataSource"?/>

????????</property>

????</bean>

????<bean?id="userDAO"?class="onlyfun.caterpillar.UserDAO">

????????<property?name="dataSource">

????????????<ref?bean="dataSource"?/>

????????</property>

????</bean>

????<bean?id="userDAOProxy"?class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">

????????<property?name="proxyInterfaces">

????????????<list>

????????????????<value>onlyfun.caterpillar.IUserDAO</value>

????????????</list>

????????</property>

????????<property?name="target">

????????????<ref?bean="userDAO"?/>

????????</property>

????????<property?name="transactionManager">

????????????<ref?bean="transactionManager"?/>

????????</property>

????????<property?name="transactionAttributes">

????????????<props>

????????????????<prop?key="insert*">PROPAGATION_REQUIRED</prop>

????????????</props>

????????????

????????</property>

????</bean>

</beans>

datasource這個bean中我們配置了數(shù)據(jù)源的相關(guān)屬性。在userDAOProxy這個bean中，我們配置了target、transactionManager、transactionAttributes屬性。在transactionAttributes中，我們指定所有insert*方法中操作會注入事務管理。

程序的運行結(jié)果是，由于在insert方法中的查詢語句出錯，會引起之前的insert語句效果被撤銷。你也可以把查詢語句先設置正確，看看效果。

posted on 2006-12-30 11:17 matthew 閱讀(958) 評論(0) 編輯收藏所屬分類: 閱讀筆記

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