Ibatis使用实践 - 2-阿里云开发者社区

Ibatis中可以将pojo中的实体的属性对应于数据库里面的字段，可以通过显示或隐式的方式进行指定。

1、pojo类： Account.java

public class Account {
   private int userid;
   private String username;
   private String password;
   private String groupname;

   public int getUserid() {
     return userid;
  }
   public void setUserid( int userid) {
     this.userid = userid;
  }
   public String getUsername() {
     return username;
  }
   public void setUsername(String username) {
     this.username = username;
  }
   public String getPassword() {
     return password;
  }
   public void setPassword(String password) {
     this.password = password;
  }
   public String getGroupname() {
     return groupname;
  }
   public void setGroupname(String groupname) {
     this.groupname = groupname;
  }

}

2、userAccount.xml

<? xml version ="1.0" encoding ="UTF-8" ?>

<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
     "http://ibatis.apache.org/dtd/sql-map-2.dtd">

< sqlMap >

   < select id ="getAllUsers" resultClass ="com.air.Account" >
    SELECT * FROM USER_ACCOUNT order by USERID
   </ select >

  
   < select id ="getAllUsers1" resultClass ="com.air.Account"
     parameterClass ="string" >
    SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName#
   </ select >

  
   < select id ="getAllUsers2" resultClass ="com.air.Account"
     parameterClass ="string" >
    SELECT USERID as userid, USERNAME as username, PASSWORD as
    password, GROUPNAME as groupname FROM USER_ACCOUNT WHERE
    GROUPNAME=#groupName#
   </ select >

  
   < select id ="getAllUsers3" resultClass ="hashmap"
     parameterClass ="string" >
    SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName#
   </ select >

  
   < resultMap id ="accoutResult" class ="com.air.Account" >
     < result property ="userid" column ="USERID" />
     < result property ="username" column ="USERNAME" />
     < result property ="password" column ="PASSWORD" />
     < result property ="groupname" column ="GROUPNAME" />
   </ resultMap >
   < select id ="getAllUsers4" resultMap ="accoutResult"
     parameterClass ="string" >
    SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName#
   </ select >

  
   < resultMap id ="mapResult" class ="hashmap" >
     < result property ="userid" column ="USERID" />
     < result property ="username" column ="USERNAME" />
     < result property ="password" column ="PASSWORD" />
     < result property ="groupname" column ="GROUPNAME" />
   </ resultMap >
   < select id ="getAllUsers5" resultMap ="mapResult"
     parameterClass ="string" >
    SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName#
   </ select >

  
   < select id ="selectXML" parameterClass ="string" resultClass ="xml"
     xmlResultName ="log" >
    SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName#
   </ select >

   < select id ="getOneUser" resultClass ="com.air.Account"
     parameterClass ="string" >
    SELECT * FROM USER_ACCOUNT WHERE GROUPNAME=#groupName#
   </ select >

  
   < insert id ="insertOneUser1" parameterClass ="com.air.Account" >
    INSERT INTO USER_ACCOUNT
    (
      USERNAME, PASSWORD, GROUPNAME
    )VALUES(
      #username#,#password#,#groupname#
    )
   </ insert >

  
   < insert id ="insertOneUser2" parameterClass ="com.air.Account" >
    INSERT INTO USER_ACCOUNT
    (
      USERNAME, PASSWORD, GROUPNAME
    )VALUES(
      #username:VARCHAR#,
      #password:VARCHAR#,
      #groupname:VARCHAR#
    )
   </ insert >

  
   < parameterMap     id ="parameterMapEx" class ="com.air.Account" >
     < parameter property ="username" jdbcType ="VARCHAR" />
     < parameter property ="password" jdbcType ="VARCHAR" />
     < parameter property ="groupname" jdbcType ="VARCHAR" />
   </ parameterMap >
   < insert id ="insertOneUser3" parameterMap ="parameterMapEx" >
    INSERT INTO USER_ACCOUNT
    (
      USERNAME, PASSWORD, GROUPNAME
    )VALUES(
      ?,?,?
    )
   </ insert >

  
   < insert id ="insertOneUser4" parameterClass ="com.air.Account" >
    INSERT INTO USER_ACCOUNT
    (
      USERID,USERNAME, PASSWORD, GROUPNAME
    )VALUES(
      #userid#,
      #username#,
      #password#,
      #groupname#
    )
     < selectKey
       keyProperty ="userid"
       resultClass ="int" >
      SELECT LAST_INSERT_ID()
     </ selectKey >
   </ insert >

  
   < parameterMap id ="pro" class ="java.util.Map" >
     < parameter property ="name" jdbcType ="VARCHAR"
              javaType ="string" mode ="IN" />
   </ parameterMap >
   < procedure id ="pro_insert" parameterMap ="pro" >
    {call new_proc(?)}
   </ procedure >

</ sqlMap >

全局文件：SqlMapConfig.xml

<? xml version ="1.0" encoding ="UTF-8" ?>

<!DOCTYPE sqlMapConfig PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"
        "http://ibatis.apache.org/dtd/sql-map-config-2.dtd">

< sqlMapConfig >

   < properties resource ="sqlmap.properties" />

     < transactionManager type ="JDBC" >
         < dataSource type ="SIMPLE" >
             < property value ="${driver}" name ="JDBC.Driver" />
             < property value ="${url}" name ="JDBC.ConnectionURL" />
             < property value ="${username}" name ="JDBC.Username" />
             < property value ="${password}" name ="JDBC.Password" />
         </ dataSource >
     </ transactionManager >

     < sqlMap resource ="userAccount.xml" />
     < sqlMap resource ="Dynamic.xml" />

</ sqlMapConfig >

。。。。待续

3、cacheModel

cacheModel的属性值等于指定的cacheModel元素的name属性值。属性cacheModel定义查询mapped statement的缓存。每一个查询mapped statement可以使用不同或相同的cacheModel。

<cacheModel id="product-cache" imlementation="LRU">
<flushInterval hours="24"/>
<flushOnExecute statement="insertProduct"/>
<flushOnExecute statement="updateProduct"/>
<flushOnExecute statement="deleteProduct"/>
<property name=”size” value=”1000” />
</cacheModel>
<statement id=”getProductList” parameterClass=”int” cacheModel=”product-cache”>
select * from PRODUCT where PRD_CAT_ID = #value#
</statement>

4、事务处理

缺省情况下，调用SqlMapClient对象的任意executeXxxx()方法将缺省地自动COMMIT/ROLLBACK。这意味着每次调用executeXxxx()方法都是一个独立的事务。这确实很简单，但对于需要在同一个事务中执行多个语句的情况（即只能同时成功或失败），并不适用。这正是事务处理要关心的事情。

如果您在使用Global Transaction（在SQL Map配置文件中设置），您可以使用自动提交并且可以得到在同一事务中执行的效果。但为了提高性能，最好是明确地划分事务的范围，因为这样做可以减少连接池的通讯流量和数据库连接的初始化。

SqlMapClient对象拥有让您定义事务范围的方法。使用下面SqlMapClient类的方法，可以开始、提交和/或回退事务：

public void startTransaction () throws SQLException

public void commitTransaction () throws SQLException

public void endTransaction () throws SQLException

开始一个事务，意味着您从连接池中得到一个连接，打开它并执行查询和更新SQL操作。

public updateItemDescription (String itemId, String newDescription) throws SQLException {
try {
sqlMap.startTransaction ();
Item item = (Item) sqlMap.queryForObject ("getItem", itemId);
item.setDescription (newDescription);
sqlMap.update ("updateItem", item);
sqlMap.commitTransaction ();
} finally {
sqlMap.endTransaction ();
}
}

注意！事务不能嵌套。在调用commit（）或rollback（）之前，从同一线程多次调用.startTransaction，将引起抛出例外。换句话说，对于每个SqlMap实例，每个线程最多只能打开一个事务。

注意！SqlMapClient事务处理使用Java的 ThreadLocal保存事务对象。这意味着在处理事务时，每个调用startTransaction（）的线程，将得到一个唯一的Connection对象。将一个Connection对象返回数据源（或关闭连接）唯一的方法是调用commitTransaction（）或rollbackTransaction（）方法。否则，会用光连接池中的连接并导致死锁。

本文转自 tianya23 51CTO博客，原文链接：http://blog.51cto.com/tianya23/386256，如需转载请自行联系原作者

Ibatis使用实践 - 2

3、cacheModel

4、事务处理

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