PageHandler使用及扩展

public interface PageHandler {

    /**
     * 是否支持当前数据库的分页
     *
     * @param dialect
     * @return
     */
    boolean support(String dialect);

    /**
     * 根据查询语句获取count语句
     *
     * @param command 
     * @param dialect the dialect
     * @return count command
     */
    String getCountCommand(String command, String dialect);

    /**
     * 根据查询语句获取分页语句
     *
     * @param command    the command
     * @param pagination the pagination
     * @param dialect    the dialect
     * @return page command
     */
    String getPageCommand(String command, Pagination pagination, String dialect);
}

public class PostgresqlPageHandler extends AbstractPageHandler {

    @Override
    public boolean support(String dialect) {
        return StringUtils.indexOfIgnoreCase(dialect, "postgresql") != -1;
    }

    @Override
    public String getPageCommand(String command, Pagination pagination, String dialect) {
        StringBuilder pageSql = new StringBuilder(200);
        pageSql.append(command);
        pageSql.append(" limit ");
        pageSql.append(pagination.getPageSize());
        pageSql.append(" offset ");
        pageSql.append(pagination.getBeginIndex());
        return pageSql.toString();
    }
}

<bean id="postgresqlPageHandler" class="com.sonsure.dumper.core.page.PostgresqlPageHandler"/>
<bean id="jdbcTemplateEngine" class="com.sonsure.dumper.springjdbc.config.JdbcTemplateEngineFactoryBean">
    <!-- ... -->
    <property name="pageHandler" ref="postgresqlPageHandler"/>
</bean>

<bean id="postgresqlPageHandler" class="com.sonsure.dumper.core.page.PostgresqlPageHandler"/>
<bean id="mysqlPageHandler" class="com.sonsure.dumper.core.page.MysqlPageHandler"/>
<bean id="oraclePageHandler" class="com.sonsure.dumper.core.page.OraclePageHandler"/>

<bean id="negotiatingPageHandler" class="com.sonsure.dumper.core.page.NegotiatingPageHandler">
    <property name="pageHandlers">
        <list>
            <ref bean="postgresqlPageHandler"/>
            <ref bean="mysqlPageHandler"/>
            <ref bean="oraclePageHandler"/>
        </list>
    </property>
</bean>

<bean id="jdbcTemplateEngine" class="com.sonsure.dumper.springjdbc.config.JdbcTemplateEngineFactoryBean">
    <!-- ... -->
    <property name="pageHandler" ref="negotiatingPageHandler"/>
</bean>