14mybatis_ Input mappings (passing Pojo wrapper objects)--very important

Suppose we have a requirement: A comprehensive query of user information that requires a complex query condition (which may include user information, other information, such as goods, orders)

Our idea is that parametertype, which is passed into select, is a wrapper class that can have a lot of things.

We already have a User.java PO class, but the conditions we're querying may be more complex than the user class. In order to facilitate the extension, we will extend a usercustom extend user such a class.

The cases are as follows:

Give the case structure first:

The above example illustrates the following: Sqlmapconfig.xml is the total configuration file. Mapper/usermapper.xml is the configuration file for this case. User.java is the entity class for the database. Usercustom.java is the implementation class of User.java. Userqueryvo.java is a wrapper class. Usermapper.java is the Mapper interface class. Mybatis_mappertest.java is the test code.

The first step:

The Sqlmapconfig.xml code is as follows:

<?XML version= "1.0" encoding= "UTF-8"?><!DOCTYPE configurationpublic "-//mybatis.org//dtd Config 3.0//en" "Http://mybatis.org/dtd/mybatis-3-config.dtd" ><Configuration>                  <!--The configuration of the properties must be written on top of typealiases -    <PropertiesResource= "Db.properties"></Properties><!--Configure aliases -<typealiases>    <!--define type for alias: path to type alias: Alias -    <Typealiastype= "Cn.itcast.mybatis.po.User"alias= "User"/> </typealiases>         <!--environments configuration will be abolished after the integration with spring -    <Environmentsdefault= "Development">        <EnvironmentID= "Development">        <!--using JDBC Transaction management -            <TransactionManagertype= "JDBC" />        <!--Database Connection Pool -            <DataSourcetype= "Pooled">                < Propertyname= "Driver"value= "${jdbc.driver}" />                < Propertyname= "url"value= "${jdbc.url}" />                < Propertyname= "username"value= "${jdbc.username}" />                < Propertyname= "Password"value= "${jdbc.password}" />            </DataSource>        </Environment>    </Environments>    <!--Load the mapping file (sqlmap/user.xml) into the Sqlmapconfig.xml -        <mappers>                       <!--load the mapper.xml into the Sqlmapconfig.xml -           <!--Follow some specifications: You need to keep the Mapper interface class name and the Mapper.xml mapping file name consistent and in one directory.                                             The premise of this specification is: Use the Mapper proxy method.  -            <MapperResource= "Mapper/usermapper.xml"/>                                 </mappers>            </Configuration>

Step Two:

 <?  xml version= "1.0" encoding= "UTF-8"  ?>  <!  doctype mapperpublic "-//mybatis.org//dtd Mapper 3.0//en" "http://mybatis.org/dtd/ Mybatis-3-mapper.dtd " >  <!--   Nanmespace: namespace. The function is to classify the SQL management, understand SAL separation Note: Using Mapper Proxy method, namespace has a special important role  -->  Span style= "color: #0000ff;" ><  mapper  namespace  = "Cn.itcast.mybatis.mapper.userMapper"  >  <!--   

 use  rqueryvo has a usercustom inside, #{usercustom.sex} is written in Userqueryvo  the properties inside ( Usercustom ) Properties (sex )  

    -    <  ID= "Finduserlist"  parametertype= "Cn.itcast.mybatis.po.UserQueryVo" Resulttype = "Cn.itcast.mybatis.po.UserCustom" >         SELECT * from USER WHERE user.sex= #{usercustom.sex} and User.username=#{usercustom.username}      </ Select >   </ Mapper >

Step Three:

User.java Code and Usercustom.java:

 PackageCn.itcast.mybatis.po;Importjava.util.Date; Public classUser {Private intId//PRIMARY KeyPrivateString username;//the name of the userPrivateDate birthday;//BirthdayPrivateString sex;//SexPrivateString address;//Address Public intgetId () {returnID;} Public voidSetId (intID) { This. ID =ID;} PublicString GetUserName () {returnusername;} Public voidSetusername (String username) { This. Username =username;} PublicDate Getbirthday () {returnbirthday;} Public voidsetbirthday (Date birthday) { This. Birthday =birthday;} PublicString Getsex () {returnsex;} Public voidsetsex (String sex) { This. Sex =sex;} PublicString getaddress () {returnaddress;} Public voidsetaddress (String address) { This. Address =address;}}

 Package Cn.itcast.mybatis.po;  Public class extends User {}

Fourth step: Write Userqueryvo.java Packaging class

 Package Cn.itcast.mybatis.po;  Public class Userqueryvo {    // User's query conditions private  usercustom usercustom;  Public Usercustom Getusercustom () {    return  usercustom;}  Public void Setusercustom (Usercustom usercustom) {    this. usercustom = Usercustom;}} 

Fifth step: Usermapper.java is the Mapper interface class

 PackageCn.itcast.mybatis.mapper;Importjava.util.List;ImportCn.itcast.mybatis.po.User;ImportCn.itcast.mybatis.po.UserCustom;ImportCn.itcast.mybatis.po.UserQueryVo; Public InterfaceUsermapper {//the name (Finduserbyid) is identical to the ID inside the usermapper.xml.//Note that the returned list is written here. SelectList is called inside the code, but in Usermapper.xml it's written//resulttype= "Cn.itcast.mybatis.po.User"/** <select id= "finduserlist" parametertype= "Cn.itcast.mybatis.po.UserQueryVo" resulttype= " Cn.itcast.mybatis.po.UserCustom "> select * from USER WHERE user.sex= #{usercustom.sex} and User.username=#{userc Ustom.username} </select> * **/ PublicList<usercustom>finduserlist (Userqueryvo userqueryvo);}

Sixth step:

Write the Mybatis_mappertest.java test code.

 PackageCn.itcast.mybatis.first;Importjava.io.IOException;ImportJava.io.InputStream;Importjava.util.Date;Importjava.util.List;Importorg.apache.ibatis.io.Resources;Importorg.apache.ibatis.session.SqlSession;Importorg.apache.ibatis.session.SqlSessionFactory;ImportOrg.apache.ibatis.session.SqlSessionFactoryBuilder;ImportOrg.junit.Before;Importorg.junit.Test;ImportCn.itcast.mybatis.Dao.UserMapper;ImportCn.itcast.mybatis.mapper.userMapper;ImportCn.itcast.mybatis.po.User;ImportCn.itcast.mybatis.po.UserCustom;ImportCn.itcast.mybatis.po.UserQueryVo; Public classMybatis_mappertest {Privatesqlsessionfactory sqlsessionfactory; @Before Public voidSetup ()throwsIOException {String resource= "Sqlmapconfig.xml"; InputStream InputStream=Resources.getresourceasstream (Resource); //The main generation is sqlsessionfactory.          This. sqlsessionfactory=NewSqlsessionfactorybuilder (). Build (InputStream); } @Test Public voidTestmaper () {sqlsession sqlsession=NULL; Sqlsession=sqlsessionfactory.opensession (); //Generate proxy classUsermapper Usermapper=sqlsession.getmapper (Usermapper.class); //Create wrapper objects, set query criteriaUserqueryvo userqueryvo=NewUserqueryvo (); Usercustom Usercustom=NewUsercustom (); Usercustom.setsex ("1"); Usercustom.setusername (King); //Set query criteria for a wrapper classUserqueryvo.setusercustom (Usercustom);                    Usermapper.finduserlist (USERQUERYVO); }}

Result: normal operation.

14mybatis_ Input mappings (passing Pojo wrapper objects)--very important