Mybatis-using where to dynamically stitch SQL

I. Creating Projects and Databases
Project Name: mybatis092901
Database name: mybatis0929
Table Name: Dept
CREATE TABLE ' Dept ' (
' DeptNo ' int (one) is not NULL,
' Deptname ' varchar (+) DEFAULT NULL,
' Location ' varchar (+) DEFAULT NULL,
PRIMARY KEY (' DeptNo ')
) Engine=innodb DEFAULT Charset=utf8;
Table Name: EMP
CREATE TABLE ' emp ' (
' Empno ' int (one) is not NULL,
' ename ' varchar (+) DEFAULT NULL,
' HireDate ' Date DEFAULT NULL,
' Job ' varchar (+) DEFAULT NULL,
' Sal ' Double DEFAULT NULL,
' Mgr ' varchar (+) DEFAULT NULL,
' Comm ' varchar (+) DEFAULT NULL,
' Deptno ' int (one) DEFAULT NULL,
PRIMARY KEY (' empno ')
) Engine=innodb DEFAULT Charset=utf8;
Second, add Jar package
1. Create a Lib directory on the project
/lib
2. Add the jar in the Lib directory
Junit-4.10.jar
Mybatis-3.2.2.jar
Mysql-connector-java-5.1.10-bin.jar
Third, add the configuration file
1. Create the Conf directory on the project
/conf
2. Add a configuration file under the Conf directory
Configuration file name: Mybatis-config.xml
Configuration file Contents:
<?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>
<typeAliases>
<typealias alias= "Emp" type= "Cn.jbit.mybatis092901.domain.Emp"/>
</typeAliases>
<environments default= "Development" >
<environment id= "Development" >
<transactionmanager type= "JDBC"/>
<datasource type= "Pooled" >
<property name= "Driver" value= "Com.mysql.jdbc.Driver"/>
<property name= "url" value= "jdbc:mysql://localhost:3306/mybatis0929"/>
<property name= "username" value= "root"/>
<property name= "Password" value= "root"/>
</dataSource>
</environment>
</environments>
</configuration>
Iv. Creating an Entity class
1. Create the package in the SRC directory
Package Name: Cn.jbit.mybatis092901.domain
2. Create an entity class under a package
Class Name: Dept.java
Content:
public class Dept implements Serializable {
Private Integer deptno;//Department number
Private String deptname;//Department name
Private String location;//Department address
Omit Get and set
}
Class Name: Emp.java
Content:
public class Emp implements Serializable {
Employee Name
Private String EmpName;
Employee number
Private Integer EmpNo;
Employee onboarding Hours
Private Date hiredate;
Staff positions
Private String job;
Employee wages
Private Double salary;
Manager number
Private Integer Mgr;
Bonus
Private Double comm;
Department number
Private Integer DeptNo;
Omit Get and set
}
Five, durable layer design
1. Interface design
1). Create a package in the SRC directory
Package Name: Cn.jbit.mybatis092901.dao
2). Create an interface under a package
Interface Name: Iempdao.java
Contents of the interface:
Public interface Iempdao {
/**
* Use where
* @param emp
* @return
*/
Public list<emp> findempbyexamplewhere (EMP emp);
}
Vi. adding related mapping files
1. Add a configuration file under Conf
Mapping file name: Empdaomapper.xml
Map File Contents:
<?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= "Cn.jbit.mybatis092901.dao.IEmpDao" >
<resultmap id= "Empresultmap" type= "CN.JBIT.MYBATIS092901.DOMAIN.EMP" >
<id property= "EmpNo" column= "EmpNo"/>
<result property= "EmpName" column= "ename"/>
<result property= "HireDate" column= "HireDate"/>
<result property= "Job" column= "job"/>
<result property= "Salary" column= "Sal"/>
<result property= "comm" column= "comm"/>
</resultMap>
<!--
Using where for dynamic SQL stitching
-
<select id= "Findempbyexamplewhere" parametertype= "Emp" resultmap= "Empresultmap" >
SELECT * from EMP
<where>
<if test = "DeptNo! = null" >
and deptno= #{deptno}
</if>
<if test = "EmpName! = null" >
and ename like #{empname}
</if>
</where>
</select>
</mapper>
Seven. Persistence layer Implementation Class design
1). Create the package in the SRC directory
Package Name: Cn.jbit.mybatis092901.dao.impl
2). Create the implementation class under the package
Implementation class Name: Empdaoimpl.java
Implement the contents of the class:
/**
* In order to use the code to look clear, Sqlsession's acquisition uses the tool class
*/
@Override
public void Insertemp (EMP emp) {
String resource = "Mybatis-config.xml";
Reader reader = null;
Sqlsessionfactory factory = null;
sqlsession session = NULL;
try {
Reader = Resources.getresourceasreader (Resource);
Sqlsessionfactorybuilder builder = new Sqlsessionfactorybuilder ();
Factory = Builder.build (reader);
Session = Factory.opensession ();
list<emp> emplist = new ArrayList ();
Emplist = Session.selectlist ("cn.jbit.mybatis092901.dao.IEmpDao.findEmpByExampleIf", EMP);
} catch (Exception E1) {
E1.printstacktrace ();
}finally {
Session.close ();
}
}
Viii. Adding a mapping file reference in a configuration file
1. Add mapper in the Mybatis-fonfig.xml file
<mappers>
<mapper resource= "Empdaomapper.xml"/>
</mappers>
Nine, test operation
1. Create the test catalog in the project
/test
2. Create a package in the test directory
Cn.jbit.mybatis092901.dao
3. Create a test class under a package
Class Name: Empdaotest.java
Content:
public class Empdaotest {
Persistence layer implementations for employee classes
private static Iempdao Empdao = new Empdaoimpl ();
/**
* Test where
*/
@Test
public void Testwhere () {
EMP emp = new EMP ();
Emp.setdeptno (9);
Emp.setempname ("Zhang Ping U");
list<emp> emps = Empdao.findempbyexamplewhere (EMP);
Printemplist (Emps);
}
private void Printemplist (list<emp> emplist) {
for (Emp emp:emplist) {
Printemp (EMP);
}
}
}

This article is from the "Yan" blog, please be sure to keep this source http://suyanzhu.blog.51cto.com/8050189/1559319

Mybatis-using where to dynamically stitch SQL