本期开始讲Model层的开发,整合iBatis框架,iBatis是Apache旗下Java数据持久层的框架,跟Hibernate是同一类型的框架。大家可到它的官方网站去下载http://ibatis.apache.org/java.cgi,如下图:
我这里下载的是当前最新版本iBatis 2.3.4 , 下载之后,解压包是这样的:
我们在lib目录下,找到“ibatis-2.3.4.726.jar”文件,加入到我们项目的lib目录下,就行。在这里,我们先说下怎么学习这个iBatis框架:上图中,有个simple_example的文件夹,它里面就包含了一个超级简单且容易理解的例子,大家可以去学习一下。By the way,如果你学过Hibernate的话,你会发觉iBatis要比Hibernate好学很多。关于Hibernate和iBatis的争论,网上有很多,大家有兴趣可以去了解一下。
好,我们先建立数据库和设计数据库吧。我这项目用的是MySQL 5.0。生成数据库和数据表的SQL语句如下:
create database simpledb; create table article |
这是我们常见的新闻表及其中的字段。
接下来,写一个与表对应的新闻类,Article.java,这个其实是POJO类,代码如下:
import java.util.Date;
public class Article {
private int id;
private String title;
private String author;
private String content;
private Date pubtime;
/** *//***********getter和setter方法***********/
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public Date getPubtime() {
return pubtime;
}
public void setPubtime(Date pubtime) {
this.pubtime = pubtime;
}
}
有了数据表和实体类,现在来写两者之间映射的配置文件Article.xml。代码如下:
<! DOCTYPE sqlMap
PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
"http://ibatis.apache.org/dtd/sql-map-2.dtd" >
< sqlMap namespace ="Article" >
<!-- Use type aliases to avoid typing the full classname every time. -->
< typeAlias alias ="Article" type ="cn.simple.pojo.Article" />
<!--
Result maps describe the mapping between the columns returned from a
query, and the class properties. A result map isn't necessary if the
columns (or aliases) match to the properties exactly.
-->
< resultMap id ="ArticleResult" class ="Article" >
< result property ="id" column ="ID" />
< result property ="title" column ="TITLE" />
< result property ="author" column ="AUTHOR" />
< result property ="content" column ="CONTENT" />
< result property ="pubtime" column ="PUBTIME" />
</ resultMap >
<!--
Select with no parameters using the result map for Account class.
-->
< select id ="selectAllArticles" resultMap ="ArticleResult" >
select * from article
</ select >
<!--
A simpler select example without the result map. Note the aliases to
match the properties of the target result class.
-->
< select id ="selectArticleById" parameterClass ="int" resultClass ="Article" >
select
ID as id,
TITLE as title,
AUTHOR as author,
CONTENT as content,
PUBTIME as pubtime
from Article
where ID=#id#
</ select >
<!-- Insert example, using the Account parameter class -->
< insert id ="insertArticle" parameterClass ="Article" >
insert into article (
TITLE,
AUTHOR,
CONTENT,
PUBTIME
) values (
#title#,
#author#,
#content#,
#pubtime#
)
</ insert >
<!-- Update example, using the Account parameter class -->
< update id ="updateArticle" parameterClass ="Article" >
update article set
TITLE = #title#,
AUTHOR = #author#,
CONTENT = #content#,
PUBTIME = #pubtime#
where
ID = #id#
</ update >
<!-- Delete example, using an integer as the parameter class -->
< delete id ="deleteArticleById" parameterClass ="int" >
delete from article where ID = #id#
</ delete >
</ sqlMap >
大家不要觉得这个映射文件很复杂,其实,这挺容易理解的,如果大家赖得写的话,可复制iBatis自带的simple_example下的例子的映射文件,然后修改一下就行。
有了表、实体类、表与实体之间的映射文件,之后,该做什么呢?学过Hibernate的朋友会想到那个数据库连接信息的配置文件,当然,iBatis也需要类似的文件,即SqlMapConfig.xml,代码如下:
<! DOCTYPE sqlMapConfig
PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"
"http://ibatis.apache.org/dtd/sql-map-config-2.dtd" >
< sqlMapConfig >
<!-- Configure a built-in transaction manager. If you're using an
app server, you probably want to use its transaction manager
and a managed datasource -->
< transactionManager type ="JDBC" commitRequired ="false" >
< dataSource type ="SIMPLE" >
< property name ="JDBC.Driver" value ="com.mysql.jdbc.Driver" />
< property name ="JDBC.ConnectionURL" value ="jdbc:mysql://localhost:3306/simpledb" />
< property name ="JDBC.Username" value ="root" />
< property name ="JDBC.Password" value ="root" />
</ dataSource >
</ transactionManager >
<!-- List the SQL Map XML files. They can be loaded from the
classpath, as they are here (com.domain.data) -->
< sqlMap resource ="cn/simple/pojo/Article.xml" />
<!-- List more here
<sqlMap resource="com/mydomain/data/Order.xml"/>
<sqlMap resource="com/mydomain/data/Documents.xml"/>
-->
</ sqlMapConfig >
一看这代码,也有点复杂,我的说法同上,大不了COPY,再略作修改,呵呵
好了,来写我们的业务逻辑层:
import java.io.IOException;
import java.io.Reader;
import java.sql.SQLException;
import java.util.List;
import cn.simple.pojo.Article;
import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.client.SqlMapClient;
import com.ibatis.sqlmap.client.SqlMapClientBuilder;
public class ArticleManager {
/** *//**
* SqlMapClient instances are thread safe, so you only need one. In this
* case, we'll use a static singleton. So sue me. ;-)
*/
private static SqlMapClient sqlMapper;
/** *//**
* It's not a good idea to put code that can fail in a class initializer,
* but for sake of argument, here's how you configure an SQL Map.
*/
static {
try {
Reader reader = Resources.getResourceAsReader("SqlMapConfig.xml");
sqlMapper = SqlMapClientBuilder.buildSqlMapClient(reader);
reader.close();
} catch (IOException e) {
// Fail fast.
throw new RuntimeException(
"Something bad happened while building the SqlMapClient instance."
+ e, e);
}
}
/** *//**
* 查询列表
* @return
* @throws SQLException
*/
public static List<Article> selectAllArticles() throws SQLException {
return sqlMapper.queryForList("selectAllArticles");
}
/** *//**
* 插入数据
* @param article
* @throws SQLException
*/
public static void insertArticle(Article article) throws SQLException {
sqlMapper.insert("insertArticle", article);
}
/** *//**
* 更新数据
* @param article
* @throws SQLException
*/
public static void updateArticle(Article article) throws SQLException {
sqlMapper.update("updateArticle", article);
}
/** *//**
* 删除数据
* @param id
* @throws SQLException
*/
public static void deleteArticle(int id) throws SQLException {
sqlMapper.delete("deleteArticleById", id);
}
/** *//**
* 单查数据
* @param id
* @return
* @throws SQLException
*/
public static Article queryArticleById(int id) throws SQLException {
Article article = (Article)sqlMapper.queryForObject("selectArticleById", id);
return article;
}
}
写一个Junit测试类来测试一下吧,代码如下:
import java.sql.SQLException;
import java.util.Date;
import java.util.List;
import org.junit.Test;
import cn.simple.pojo.Article;
public class ArticleManagerTest {
@Test
public void testSelectAllArticles() throws SQLException {
List<Article> list = ArticleManager.selectAllArticles();
for(Article a : list){
System.out.println(a.getTitle() + a.getAuthor() + a.getContent() + a.getPubtime());
}
}
@Test
public void testInsertArticle() throws SQLException {
for(int i=0; i<10; i++){
Article article = new Article();
article.setTitle("title-" + i);
article.setAuthor("author-" + i);
article.setContent("content-" + i);
article.setPubtime(new Date());
ArticleManager.insertArticle(article);
}
}
@Test
public void testUpdateArticle() throws SQLException {
Article article = new Article();
article.setId(3);
article.setTitle("title-title");
article.setAuthor("author-author");
ArticleManager.updateArticle(article);
}
@Test
public void testDeleteArticle() throws SQLException {
ArticleManager.deleteArticle(5);
}
}
到此,我们的项目文件列表截图如下:
新闻管理的Model层开发完毕,可以供我们的Action调用了,好,Struts 2.1.6 精简实例系列教程,敬请大家期待下文!
本文原创,转载请注明出处,谢谢!http://www.blogjava.net/rongxh7(心梦帆影JavaEE技术博客)