四、spring集成ibatis进行项目中dao层基类封装

　　Apache iBatis（现已迁至Google Code下发展，更名为MyBatis）是当前IT项目中使用很广泛的一个半自动ORM框架，区别于Hibernate之类的全自动框架，iBatis对数据库的操作拥有更加灵活的控制，对于那些经常需要调用本地数据库函数自定义SQL语句，或是喜欢自己优化SQL执行效率的开发者来说，iBatis是一个非常不错的选择。而得到广泛应用的开源企业架构SpringFramework，也很好的将其进行了集成，使得iBatis在 SpringFramework中的使用更加便利、快捷。开发者所要做的就是继承SpringFramework中提供的SqlMapClientDaoSupport类即可。下面将简单介绍使用spring中集成的ibatis进行项目中dao层基类封装，以方便开发。

1、SqlMapClientFactoryBean 的装配

　　SqlMapClientFactoryBean是SqlMapClientTemplate使用的基础，如果在SpringFramework应用中没有装配SqlMapClientFactoryBean，那么SqlMapClientTemplate将不可用，报空指针错误。其配置信息如下：（关于数据源、事务管理、url拦截器等更多配置请参看博文https://www.cnblogs.com/jiarui-zjb/p/8710361.html）

<bean id="sqlMapClient"
    class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
    <!-- iBatis sqlmap config 文件位置 -->
    <property name="configLocation">
        <value>
            /WEB-INF/classes/org/bussiness/config/ibatis/SqlMapConfig.xml
        </value>
    </property>
    <!-- 在SpringFramework配置文件中使用的数据源 -->
    <property name="dataSource">
        <ref local="dataSource" />
    </property>
    <!-- 如果需要读写Lob字段，需要注入在SpringFramework配置文件中配置好的Handler，这里是Oracle的数据库 -->
    <property name="lobHandler" ref="oracleLobHandler"/>
</bean>

2、继承使用SqlMapClientDaoSupport类

2.1）首先定义一个IBaseDao接口提供各种场景的查询、修改、删除、分页查询的各种抽象功能方法

package org.biframework.dao.ibatis;
import com.ibatis.common.util.PaginatedList;
import java.util.List;
import org.biframework.exception.DaoException;
public abstract interface IBaseDao
{
  public abstract Object getObject(String paramString, Object paramObject)
    throws DaoException;

  @SuppressWarnings("unchecked")
  public abstract List getList(String paramString, Object paramObject)
    throws DaoException;

  public abstract PaginatedList getPgntList(String paramString1, Object paramObject, String paramString2)
    throws DaoException;

  public abstract PaginatedList getPgntList(String paramString1, Object paramObject, String paramString2, int paramInt)
    throws DaoException;

  @SuppressWarnings("unchecked")
  public abstract List getListUseSameStmt(String paramString, Object[] paramArrayOfObject)
    throws DaoException;

  public abstract int update(String paramString, Object paramObject)
    throws DaoException;

  public abstract int transUpdateSameOpt(String paramString, Object[] paramArrayOfObject)
    throws DaoException;

  public abstract int transUpdate(Object[][] paramArrayOfObject)
    throws DaoException;

  @SuppressWarnings("unchecked")
  public List getList(String statementName, Object parameterObject,
            int skipResults, int maxResults) throws DaoException;
}

备注：该层也可以不写

2.2）继承使用SqlMapClientDaoSupport类并实现IBaseDao接口

package org.biframework.dao.ibatis;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.biframework.exception.DaoException;
import org.springframework.orm.ibatis.support.SqlMapClientDaoSupport;

import com.ibatis.common.util.PaginatedList;

public class BaseDao extends SqlMapClientDaoSupport implements IBaseDao {

    @SuppressWarnings("unused")
    private static Log log;
    protected static final int PAGE_SIZE = 15;
    @SuppressWarnings("unchecked")
    static Class class$0; /* synthetic field */

    public BaseDao() {
    }
    /*
    使用spring中集成的ibatis实现数据的查询、修改、删除
    1）当请求参数被封装为一个普通对象，查询结果为List集合：
    使用queryForList返回List 源码方法如下：getSqlMapClientTemplate()，获取SqlMapClientTemplate对象，
    参数说明：a、statementName sql声明；b、parameterObject请求参数对象 queryForList方法源码如下
    public List queryForList(String statementName, Object parameterObject)
      throws DataAccessException
      {
        executeWithListResult(new SqlMapClientCallback()
        {
          private final String val$statementName;
          private final Object val$parameterObject;
          public Object doInSqlMapClient(SqlMapExecutor executor)
            throws SQLException
          {
            return executor.queryForList(this.val$statementName, this.val$parameterObject);
          }
        });
      }
    */
    @SuppressWarnings("unchecked")
    public List getList(String statementName, Object parameterObject)
            throws DaoException {
        List list = getSqlMapClientTemplate().queryForList(statementName,
                parameterObject);
        return list;
    }

    /*
    2）当请求参数被封装为一个数组对象时：
        即使用数组存放多个传参对象(obj1、obj2...)而后使用相同sql,进行多次查询，将多次查询的结果list1、list2...放到结果集List中)
    使用queryForList返回List 封装的方法如下：
    */
    @SuppressWarnings("unchecked")
    public List getListUseSameStmt(String statementName, Object objectParam[])
            throws DaoException {
        List list = null;
        List temp = null;
        if (statementName == null || objectParam == null|| objectParam.length == 0){
            return list;
        }else{
            for (int i = 0; i < objectParam.length; i++) {
                if (list == null){
                    list = new ArrayList();
                    temp = getSqlMapClientTemplate().queryForList(statementName,objectParam[i]);
                }
                if (temp != null){
                    list.addAll(temp);
                }
            }
        }
        return list;
    }

    /*
    3）当请求参数被封装为一个普通对象，查询结果为Object对象
    */
    @SuppressWarnings("unchecked")
    public Object getObject(String statementName, Object parameterObject)
            throws DaoException {
        Object result = null;
        List list = getSqlMapClientTemplate().queryForList(statementName,parameterObject);
        if (list != null && list.size() > 0){
            result = list.get(0);
        }
        return result;
    }

    /*
    4）ibatis-common-2.jar、使用ibatis自身封装的PaginatedList工具类进行分页查询，每页15条数据。
    public PaginatedList queryForPaginatedList(String statementName, Object parameterObject, int pageSize)
    throws DataAccessException
      {
        if (((this.sqlMapClient instanceof ExtendedSqlMapClient)) && (((ExtendedSqlMapClient)this.sqlMapClient).getDelegate().getTxManager() == null)) {
          throw new InvalidDataAccessApiUsageException("SqlMapClient needs to have DataSource to allow for lazy loading - specify SqlMapClientFactoryBean's 'dataSource' property");
        }
        (PaginatedList)execute(new SqlMapClientCallback()
        {
          private final String val$statementName;
          private final Object val$parameterObject;
          private final int val$pageSize;

          public Object doInSqlMapClient(SqlMapExecutor executor)
            throws SQLException
          {
            return executor.queryForPaginatedList(this.val$statementName, this.val$parameterObject, this.val$pageSize);
          }
        });
      }
    */
    public PaginatedList getPgntList(String statementName,
            Object parameterObject, String pageDirection) throws DaoException {
        PaginatedList list = getSqlMapClientTemplate().queryForPaginatedList(
                statementName, parameterObject, 15);
        if ("next".equals(pageDirection))
            list.nextPage();
        else if ("previous".equals(pageDirection))
            list.previousPage();
        else if ("first".equals(pageDirection))
            list.isFirstPage();
        else if ("last".equals(pageDirection))
            list.isLastPage();
        return list;
    }

    /*
    4）自己指定分页查询的数量
    */
    public PaginatedList getPgntList(String statementName,
            Object parameterObject, String pageDirection, int pageSize)
            throws DaoException {
        PaginatedList list = getSqlMapClientTemplate().queryForPaginatedList(
                statementName, parameterObject, pageSize);
        if ("next".equals(pageDirection)) {
            System.out.println("下一页");
            list.nextPage();
        } else if ("previous".equals(pageDirection)) {
            System.out.println("上一页");
            list.previousPage();
        } else if ("first".equals(pageDirection)) {
            System.out.println("首页");
            list.isFirstPage();
        } else if ("last".equals(pageDirection)) {
            System.out.println("末页");
            list.isLastPage();
        }
        return list;
    }

    /*
    5）该方法暂时未理解其主要是处于何种场景使用
    */
    public int update(String statementName, Object parameterObject)
    throws DataAccessException
      {
        Integer result = (Integer)execute(new SqlMapClientCallback()
        {
          private final String val$statementName;
          private final Object val$parameterObject;
          public Object doInSqlMapClient(SqlMapExecutor executor)
            throws SQLException
          {
            return new Integer(executor.update(this.val$statementName, this.val$parameterObject));
          }
        });
        return result.intValue();
      }
    */
    public int transUpdate(Object statementAndparameter[][])
            throws DaoException {
        Object statements[] = statementAndparameter[0];
        Object parameters[] = statementAndparameter[1];
        int result = 0;
        for (int i = 0; i < statements.length; i++) {
            String name = (String) statements[i];
            Object param = parameters[i];
            result += getSqlMapClientTemplate().update(name, param);
        }
        return result;
    }

    /*
    6）请求参数被封装为一个数组对象，返回结果为成功更新的记录数使用spring封装的update方法进行更新操作
    */
    public int transUpdateSameOpt(String statementName, Object objectParam[])
            throws DaoException {
        int result = 0;
        if (statementName == null || objectParam == null
                || objectParam.length == 0)
            return result;
        for (int i = 0; i < objectParam.length; i++)
            result += getSqlMapClientTemplate().update(statementName,
                    objectParam[i]);
        return result;
    }
    /*
    7）请求参数被封装为一个普通对象，返回结果为成功更新的记录数
    */
    public int update(String statementName, Object parameterObject)
            throws DaoException {
        int result = getSqlMapClientTemplate().update(statementName,
                parameterObject);
        return result;
    }

    static {
        log = LogFactory.getLog(org.biframework.dao.ibatis.BaseDao.class);
    }

    /*
    8）请求参数被封装为一个普通对象，并对查询的结果记录指定跳跃数和最大结果集
    */
    @SuppressWarnings("unchecked")
    public List getList(String statementName, Object parameterObject,
            int skipResults, int maxResults) throws DaoException {
        return getSqlMapClientTemplate().queryForList(statementName,
                parameterObject, skipResults, maxResults);
    }
}

3、进行dao层配置，并进行查询等操作

3.1）所有的dao层都继承BaseDao类

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.biframework.dao.ibatis.BaseDao;
import org.biframework.exception.DaoException;
import org.bussiness.product.detailquery.bo.StPolicyBean;

public class StPolicyDao extends BaseDao {
    protected static Log log = LogFactory.getLog(StPolicyDao.class);

    @SuppressWarnings("unchecked")
    public List getStPerm(StPBean param) throws DaoException{
        return super.getList("getShortPrem", param);
    }

    public Object getStPermCount(StPBean param) throws DaoException{
        return super.getObject("getShortPremCount", param);
    }
    }
}

3.2）进行dao装配   detailQuery-applicationContext.xml

<bean id="nstpDao" class="org.bussiness.product.detailquery.dao.NstPolicyDao">
    <property name="dataSource">
        <ref bean="dataSource" />
    </property>
    <property name="sqlMapClient">
        <ref bean="sqlMapClient" />
    </property>
</bean>

参看博文：http://sharkl.iteye.com/blog/745615