转载联合查询 in ibatis

ibatis的联合查询

(2011-06-29 11:17:29)

和一般查询区别不同的有三个地方

1、首先是实体里面，以前存的是string 现在肯定要修改为对象

package bean;

import java.sql.Timestamp;
import java.util.Date;

import baseparam.DeptBean;//存对象

public class StudentBean
{
private String id;

private String name;

private String email;

private Date birthday;

private DeptBean dept;

public DeptBean getDept()
{
return dept;
}

public void setDept(DeptBean dept)
{
this.dept = dept;
}

public String getId()
{
return id;
}

public void setId(String id)
{
this.id = id;
}

public Date getBirthday()
{
return birthday;
}

public void setBirthday(Date birthday)
{
this.birthday = birthday;
}

public String getName()
{
return name;
}

public void setName(String name)
{
this.name = name;
}

public String getEmail()
{
return email;
}

public void setEmail(String email)
{
this.email = email;
}

public StudentBean(String name)
{
super();
this.name = name;
}

public StudentBean()
{
super();
}

}

2、在配置文件中指定部门实体路径（/ibatis/src/SqlMapConfig.xml）

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN"
"http://ibatis.apache.org/dtd/ibatis-3-config.dtd">
<configuration>
<typeAliases>
  <typeAlias type="bean.StudentBean" alias="studentBean" />

  
  <typeAlias type="baseparam.DeptBean" alias="deptBean"/>
</typeAliases>

<environments default="development">
  <environment />
</mappers>
</configuration>

3、最后一个就是修改mapper文件了（/ibatis/src/Student.xml）

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

其他地方和一般的配置一样

最后测试类

public void getAll()
{
  StudentDao dao = new StudentDaoImpl();

  List<StudentBean> students = dao.getAllStudents();

  for(StudentBean c : students)
  {
   DeptBean dept = c.getDept();
   System.out.println("student'id is\t" + c.getId());
   System.out.println("student'name is\t" + c.getName());
   if(dept != null)
   {

    System.out.println("dept'name is\t" + dept.getName());
   }
   System.out.println("------------------------------");
  }
}