spring-ibatis结构解析

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"
 default-autowire="byName">

 <bean id="propertyConfigurer"
  class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <property name="locations">
   <list><!--<value>META-INF/jdbc.properties</value> --></list>
  </property>
 </bean>

 <bean id="datasource" class="数据源实现类">
  <property name="url" value="${jdbc.url}" />
  <property name="driverClassName" value="${jdbc.driverClassName}" />
  <property name="user" value="${jdbc.username}" />
  <property name="password" value="${jdbc.password}" />
  <property name="minPoolSize" value="2" />
  <property name="maxPoolSize" value="200" />
 </bean>
 
 <bean id="sqlMapClient" class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
  <property name="configLocation" value="META-INF/sqlMapConfig.xml" />
  <property name="dataSource" ref="datasource" />
 </bean>
 
 <!-- 抽象的数据库访问实现 -->
 <bean abstract="true" id="abstractDao" class="com.jnkj.dao.AbstractDao">
  <property name="sqlMapClient" ref="sqlMapClient" />
  <property name="dataSource" ref="datasource" />
 </bean>
 
 <!-- DAO定义 继承了抽象公用的dao之后，不用每个dao都配置一个property的属性 -->
 <bean id="deptDAO" parent="abstractDao" class="com.jnkj.dao.DeptDAOImpl" />

</beans>

分析：

当service层调用deptDAO后，会直接实例化abstractDao,但是abstractDao本身没有配置的属性，
所以得从父类找寻属性，找到abstractDao，有extends SqlMapClientDaoSupport，所以找到SqlMapClientDaoSupport

public abstract class SqlMapClientDaoSupport extends DaoSupport {

 private SqlMapClientTemplate sqlMapClientTemplate = new SqlMapClientTemplate();

 private boolean externalTemplate = false;

 public final void setDataSource(DataSource dataSource) {
  if (!this.externalTemplate) {
    this.sqlMapClientTemplate.setDataSource(dataSource);
  }
 }

 public final DataSource getDataSource() {
  return this.sqlMapClientTemplate.getDataSource();
 }

 public final void setSqlMapClient(SqlMapClient sqlMapClient) {
  if (!this.externalTemplate) {
   this.sqlMapClientTemplate.setSqlMapClient(sqlMapClient);
  }
 }

 public final SqlMapClient getSqlMapClient() {
  return this.sqlMapClientTemplate.getSqlMapClient();
 }

 public final void setSqlMapClientTemplate(SqlMapClientTemplate sqlMapClientTemplate) {
  Assert.notNull(sqlMapClientTemplate, "SqlMapClientTemplate must not be null");
  this.sqlMapClientTemplate = sqlMapClientTemplate;
  this.externalTemplate = true;
 }

 public final SqlMapClientTemplate getSqlMapClientTemplate() {
   return this.sqlMapClientTemplate;
 }

}
虽然没有相应属性，但是有对应的set，get方法,所以是可以完成初始化的。

对于setDataSource方法，是sqlMapClientTemplate 对象调用的，

又 private SqlMapClientTemplate sqlMapClientTemplate = new SqlMapClientTemplate();

我们可以看一下SqlMapClientTemplate 这个类：

public class SqlMapClientTemplate extends JdbcAccessor implements SqlMapClientOperations {

 private SqlMapClient sqlMapClient;
 public SqlMapClientTemplate() {
 }..........................

可以看出继承了JdbcAccessor ，故需要一个jdbc的数据源

对于sqlMapClient属性的初始化，在SqlMapClientFactoryBean里可以体现

SqlMapClientFactoryBean部分代码如下：

 

public class SqlMapClientFactoryBean implements FactoryBean<SqlMapClient>, InitializingBean {

 private static final ThreadLocal<LobHandler> configTimeLobHandlerHolder = new ThreadLocal<LobHandler>();
 public static LobHandler getConfigTimeLobHandler() {
  return configTimeLobHandlerHolder.get();
 }

 private Resource[] configLocations;

 private Resource[] mappingLocations;

 private Properties sqlMapClientProperties;

 private DataSource dataSource;

 private boolean useTransactionAwareDataSource = true;

 private Class transactionConfigClass = ExternalTransactionConfig.class;

 private Properties transactionConfigProperties;

 private LobHandler lobHandler;

 private SqlMapClient sqlMapClient;

 public SqlMapClientFactoryBean() {
  this.transactionConfigProperties = new Properties();
  this.transactionConfigProperties.setProperty("SetAutoCommitAllowed", "false");
 }

一大堆的属性，但是我们只需要配置dataSource，和configLocations

 

sqlMapConfig.xml的文件内容：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMapConfig PUBLIC "-//iBATIS.com//DTD SQL Map Config 2.0//EN"
    "http://ibatis.apache.org/dtd/sql-map-config-2.dtd">

<sqlMapConfig>
 <settings cacheModelsEnabled="true" enhancementEnabled="false"
  lazyLoadingEnabled="false" errorTracingEnabled="true" maxRequests="20"
  maxSessions="20" maxTransactions="10" useStatementNamespaces="false"/>

 <sqlMap resource="META-INF/sqlmap/Dept.xml"/>

</sqlMapConfig>