mybatis总结（二）

实现简单的crud，上一节已经进行最简单的查询

这次在oracle数据库中操作，就在oracle实例中操作，分别是Dept表和Emp表，所以配置文件需要改动。

1.实体类

Dept类

public class Dept {
    private int deptno;//部门编号
    private String dname;//部门名称
    private String loc;//所在地区
    private List<Emp> emps;//一对多关系

    public List<Emp> getEmps() {
        return emps;
    }
    public void setEmps(List<Emp> emps) {
        this.emps = emps;
    }
    public int getDeptno() {
        return deptno;
    }
    public void setDeptno(int deptno) {
        this.deptno = deptno;
    }
    public String getDname() {
        return dname;
    }
    public void setDname(String dname) {
        this.dname = dname;
    }
    public String getLoc() {
        return loc;
    }
    public void setLoc(String loc) {
        this.loc = loc;
    }

}

Emp类（只取几个字段，并没有把所有的列转换过来）

public class Emp {
	private int empno;//员工编号
	private String ename;//员工姓名
	private Dept dept;//部门对象
	private String job;//员工工作

	public String getJob() {
		return job;
	}
	public void setJob(String job) {
		this.job = job;
	}
	public int getEmpno() {
		return empno;
	}
	public void setEmpno(int empno) {
		this.empno = empno;
	}
	public String getEname() {
		return ename;
	}
	public void setEname(String ename) {
		this.ename = ename;
	}
	public Dept getDept() {
		return dept;
	}
	public void setDept(Dept dept) {
		this.dept = dept;
	}
}

2.数据库连接文件 db.properties

driver=oracle.jdbc.driver.OracleDriver//驱动名
url=jdbc:oracle:thin:@localhost:1521:MLDN//地址名
username=scott//用户名
password=tiger//密码

3.编写config.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

	<!-- properties属性配置文件的引入 -->
	<properties resource="db.properties"></properties>
	<!-- setting设置，调整mybaits运行行为 -->
	<settings>
	  <!-- 匹配下划线到驼峰式命名法 -->
	  <setting name="mapUnderscoreToCamelCase" value="true"/>
	  <setting name="safeRowBoundsEnabled" value="false"/>
	  <setting name="cacheEnabled" value="true"/>
	  <setting name="lazyLoadingEnabled" value="true"/>
	  <setting name="multipleResultSetsEnabled" value="true"/>
	  <setting name="useColumnLabel" value="true"/>
	  <setting name="useGeneratedKeys" value="false"/>
	  <setting name="autoMappingBehavior" value="PARTIAL"/>
	  <setting name="autoMappingUnknownColumnBehavior" value="WARNING"/>
	  <setting name="defaultExecutorType" value="SIMPLE"/>
	  <setting name="defaultStatementTimeout" value="25"/>
	  <setting name="defaultFetchSize" value="100"/>
	  <setting name="localCacheScope" value="SESSION"/>
	  <setting name="jdbcTypeForNull" value="OTHER"/>
	  <setting name="lazyLoadTriggerMethods" value="equals,clone,hashCode,toString"/>
	</settings>
	<!-- 类起别名 -->
	<typeAliases>
		<!-- <typeAlias type="com.qyxy.entity.Dept" alias="Dept"/> -->
		<package name="com.qyxy.entity"/>
	</typeAliases>
	<!-- 设置要使用的数据库环境 -->
	<environments default="development">//选择mysql配置

		<environment id="development">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="${driver}" />
				<property name="url" value="${url}" />
				<property name="username" value="${username}" />
				<property name="password" value="${password}" />
			</dataSource>
		</environment>

		<environment id="mysql">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="${jdbc.driverClassName}" />
				<property name="url" value="${jdbc.url}" />
				<property name="username" value="${jdbc.username}" />
				<property name="password" value="${jdbc.password}" />
			</dataSource>
		</environment>

	</environments>

	<!-- 定义不同的数据库厂商标识 -->
	<databaseIdProvider type="DB_VENDOR">
	  <property name="SQL Server" value="sqlserver"/>
	  <property name="DB2" value="db2"/>
	  <property name="Oracle" value="oracle" />
	  <property name="MySql" value="mysql" />
	</databaseIdProvider>

	<!-- 映射的sql文件 -->
	<mappers>
		<package name="com.qyxy.mapper"/>//所在包

	</mappers>
</configuration>

4.编写类的mapper.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.qyxy.mapper.DeptMapper">

	<select id="selectDept" resultType="Dept" databaseId="oracle">
		select *
		from dept where deptno = #{deptno}
	</select>
	<select id="findAll" resultType="Dept">
		select * from dept
	</select>
	<!-- 查询指定信息 -->
	<select id="find" resultType="Dept">
		select * from dept where
		dname=#{dname} and loc=#{loc}
	</select>
	<!-- 新增指定对象 -->
	<insert id="saveDept">
		insert into dept(deptno,dname,loc)
		values(#{deptno},#{dname},#{loc})
	</insert>
	<!-- 删除指定对象 -->
	<delete id="deleteDept">
		delete from dept where deptno=#{deptno}
	</delete>
	<!-- 修改指定对象 -->
	<update id="updateDept">
		update dept
		set dname=#{dname},loc=#{loc}
		where
		deptno=#{deptno}
	</update>

	<!-- 新增获取自动生成的主键id oracle中有效 -->
	<insert id="insertDept">
		 <selectKey keyProperty="deptno" resultType="int" keyColumn="deptno"
			order="BEFORE">
			select SEQ_DEPT_DEPTNO.nextval from dual
		</selectKey>
		insert into dept(deptno,dname,loc) values (#{deptno},#{dname},#{loc})
	</insert>	
------------------------------------------------------------------------------------------------补充
　　<!-- 新增多个对象 mysql中操作有效 -->
    　　<insert id="saveDepts" useGeneratedKeys="true" keyProperty="deptno">
       　　 insert into dept(dname,loc) values
       　　 <foreach item="item" collection="list" separator=",">
           　　 (#{item.dname},#{item.loc})
       　　 </foreach>
   　　 </insert>
</mapper>

5.写mapper接口和测试方法，这里就不一一写了，大家自己测试吧