使用Spring的jdbcTemplate进一步简化JDBC操作

先看applicationContext.xml配置文件：

Code
<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />-->import?java.math.BigDecimal;
import?java.util.ArrayList;
import?java.util.Iterator;
import?java.util.List;
import?java.util.Map;

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

import?com.r.vo.Book;

public?class?BookDao?{

????private?JdbcTemplate?jdbcT?=?(JdbcTemplate)?SpringUtil
????????????.getBean("jdbcTemplate");

????public?List?findALL()?{
????????String?sql?=?"select?*?from?BookInfo";
????????return?jdbcT.queryForList(sql);????????
????}

????public?List<Book>?findALLBooks()?{
????????List<Book>?books?=?new?ArrayList<Book>();;
????????String?sql?=?"select?*?from?BookInfo";
????????List?list?=?jdbcT.queryForList(sql);?
????????Iterator?iterator?=?list.iterator();
????????Book?book?=?null;
????????while?(iterator.hasNext())?{
????????????Map?map4book?=?(Map)?iterator.next();
????????????book?=?new?Book();
????????????book.setBid((Integer)?map4book.get("bid"));
????????????book.setBookName((String)map4book.get("bookName"));
????????????book.setBookType((String)map4book.get("bookType"));????????
????????????book.setBookPic(((BigDecimal)map4book.get("bookPic")).doubleValue()?);????????????
????????????book.setCount((Integer)?map4book.get("count"));
????????????books.add(book);
????????}
????????return?books;
????}????
????public?int?delete(int?bid){
????????String?sql?=?"delete?from?BookInfo?where?bid?=?";
????????return?jdbcT.update(sql,?new?Object[]{bid});
????}?????
????public?static?void?main(String[]?args)?{????????
????????List<Book>?books?=?new?BookDao().findALLBooks();;
????????for(Book?book:books){
????????????System.out.println(book.getBid()+","+book.getBookName()+","+book.getBookType());
????????}
????}
}

?

细心你，会发现JdbcTemplate的实例中有一系列的方法如：queryForXXX,update,delete大大简化了JDBC操作。

当然,还可以再进一步的优化一下,就是通过依赖注入，直接把jdbcTemplate注入到dao类的jdbcT字段。

先看新的applicationContext.xml配置文件：??

<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--><?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-2.5.xsd">

????<bean?id="springDSN"
????????class="org.springframework.jdbc.datasource.DriverManagerDataSource">
????????<property?name="driverClassName"
????????????value="com.microsoft.jdbc.sqlserver.SQLServerDriver">
????????</property>
????????<property?name="url"
????????????value="jdbc:microsoft:sqlserver://localhost:1433;databasename=bbs">
????????</property>
????????<property?name="username"?value="sa"></property>
????????<property?name="password"?value="sa"></property>
????</bean>

????<bean?id="jdbcTemplate"
????????class="org.springframework.jdbc.core.JdbcTemplate"?abstract="false"
????????lazy-init="false"?autowire="default"?dependency-check="default">
????????<property?name="dataSource">
????????????<ref?bean="springDSN"?/>
????????</property>
????</bean>

????<bean?id="bookDao"?class="com.yy.struts.dao.BookDao">
???????<property?name="jdbcT">
??????????<ref?bean="jdbcTemplate"?/>
???????</property>
????</bean>
</beans>

?那么新的DAO类：

<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />-->import?java.math.BigDecimal;
import?java.util.ArrayList;
import?java.util.Iterator;
import?java.util.List;
import?java.util.Map;

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

import?com.r.vo.Book;

public?class?BookDao?{

????private?JdbcTemplate?jdbcT;

????public?List?findALL()?{
????????String?sql?=?"select?*?from?BookInfo";
????????return?jdbcT.queryForList(sql);????????
????}

????public?List<Book>?findALLBooks()?{
????????List<Book>?books?=?new?ArrayList<Book>();;
????????String?sql?=?"select?*?from?BookInfo";
????????List?list?=?jdbcT.queryForList(sql);?
????????Iterator?iterator?=?list.iterator();
????????Book?book?=?null;
????????while?(iterator.hasNext())?{
????????????Map?map4book?=?(Map)?iterator.next();
????????????book?=?new?Book();
????????????book.setBid((Integer)?map4book.get("bid"));
????????????book.setBookName((String)map4book.get("bookName"));
????????????book.setBookType((String)map4book.get("bookType"));????????
????????????book.setBookPic(((BigDecimal)map4book.get("bookPic")).doubleValue()?);????????????
????????????book.setCount((Integer)?map4book.get("count"));
????????????books.add(book);
????????}
????????return?books;
????}????
????public?int?delete(int?bid){
????????String?sql?=?"delete?from?BookInfo?where?bid?=?";
????????return?jdbcT.update(sql,?new?Object[]{bid});
????}?????
????public?static?void?main(String[]?args)?{????????
????????List<Book>?books?=?new?BookDao().findALLBooks();;
????????for(Book?book:books){
????????????System.out.println(book.getBid()+","+book.getBookName()+","+book.getBookType());
????????}
????}
}通过依赖注入，对象之间的关系由SPRING来维护，这样能降低类与类的耦合度