MyBatis use of demo and cache experience

Below is a simple mybatis using demo.

Overall structure

The overall code is roughly as follows:

Pom dependency

Need to refer to two jar packages, one is MyBatis, the other is Mysql-connector-java, if it is Maven project, add the following dependencies in the Pom.

<dependency>    <groupId>org.mybatis</groupId>    <artifactid>mybatis</artifactid >    <version>3.2.3</version></dependency><dependency>    <groupid>mysql </groupId>    <artifactId>mysql-connector-java</artifactId>    <version>5.1.26</ Version></dependency>

Data preparation

Build point data for testing in MySQL:

CREATE DATABASE mybatis_test; CREATE TABLE User (age    INTEGER not NULL,    name VARCHAR (+) NOT null DEFAULT '); Insert user values (' Zhanjindong ') Insert user values (' Zhangsan ');

Configuration file

Two types of configuration files are required, one is MyBatis configuration file Mybatis-config.xml, the example is a very simple configuration, detailed configuration on the web with a lot of instructions.

<?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> <settings> <!--changes from the defaults for testing- <setting name= "cacheenabled" value= "false"/> <setting name= "Usegeneratedkeys" value= "true"/&G           T <setting name= "Defaultexecutortype" value= "Reuse"/> </settings> <typeAliases> < Typealias alias= "User" type= "Test.mybatis.User"/> </typeAliases> <environments default= "Developmen T "> <environment id=" Development "> <transactionmanager type=" jdbc "/> &lt                 ;d atasource type= "Pooled" > <property name= "Driver" value= "Com.mysql.jdbc.Driver"/> <property name= "url" value= "Jdbc:mysql://192.168.71.38:3306/mybatis_test"/&GT              <property name= "username" value= "root"/> <property name= "password" value= "123456"/> </dataSource> </environment> </environments> <mappers> <mappe   R resource= "Mappers/usermapper.xml"/> </mappers> </configuration>

The other is the data provider mapping file: Usermapper.xml in the example. This file is usually located under Src/main/resource or sub-directory MyBatis can be found, in Mybatis-config.xml by the Mappers/mapper node resource specified.

<?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= "Test.mybatis.UserMapper" >    <!--here namespace must be the path to the Usermapper interface "--    < Insert Id= "Insertuser" parametertype= "User" >        insert INTO User (name,age) VALUES (#{name},#{age})        <!-- There is no semicolon at the end of SQL, otherwise the "ORA-00911" error--    </insert>    <!--The ID must be the same    as the interface method name in the Usermapper interface-- <select id= "GetUser" resulttype= "User" parametertype= "java.lang.String" >        select * from User where name=#{ Name}    </select></mapper>  

Corresponding to this mapping file is Test.mybatis under this namespace usermapper this interface, just defines the interface to access the data table:

Package Test.mybatis;public interface Usermapper {public    void Insertuser (user user);    Public User GetUser (String name);}

Need a POJO:User.java

Package Test.mybatis;public class User {    private String name;    Private Integer age;    Public String GetName () {        return name;    }    public void SetName (String name) {        this.name = name;    }    Public Integer Getage () {        return age;    }    public void Setage (Integer age) {        this.age = age;    }    Public User (String name, Integer age) {        super ();        this.name = name;        This.age = age;    }    Public User () {        super ();    }}

Test

Through the mybatis operation of the database is a class called sqlsession, this class is generated through Sqlsessionfactory, general recommendations in the global maintenance of a sqlsessionfactory on it.

Testmybatis.java

Package Test.mybatis;import Java.io.ioexception;import Java.io.reader;import org.apache.ibatis.io.resources;import Org.apache.ibatis.session.sqlsessionfactory;import Org.apache.ibatis.session.sqlsessionfactorybuilder;public Class Mybatisutil {    private final static sqlsessionfactory sqlsessionfactory;    static {        String resource = "Mybatis-config.xml";        Reader reader = null;        try {            reader = Resources.getresourceasreader (Resource);        } catch (IOException e) {            System.out.println ( E.getmessage ());        }        Sqlsessionfactory = new Sqlsessionfactorybuilder (). build (reader);    public static Sqlsessionfactory Getsqlsessionfactory () {        return sqlsessionfactory;    }}

The test code is as follows:

Testmybatis.java

Package Test.mybatis;import Org.apache.ibatis.session.sqlsession;import Org.apache.ibatis.session.sqlsessionfactory;public class Testmybatis {static Sqlsessionfactory SqlSessionFactory = Nu    ll    static {sqlsessionfactory = Mybatisutil.getsqlsessionfactory ();        } public static void Main (string[] args) {testadd ();    GetUser ();        } public static void Testadd () {sqlsession sqlsession = sqlsessionfactory.opensession ();            try {usermapper usermapper = Sqlsession.getmapper (Usermapper.class);            User user = New User ("Lisi", New Integer (25));            Usermapper.insertuser (user);        Sqlsession.commit ();//must be submitted here, otherwise the data will not go into the database} finally {sqlsession.close ();        }} public static void GetUser () {sqlsession sqlsession = sqlsessionfactory.opensession ();            try {usermapper usermapper = Sqlsession.getmapper (Usermapper.class); User user = Usermapper.getuser ("Zhangsan ");        System.out.println ("Name:" + user.getname () + "|age:" + user.getage ());        } finally {sqlsession.close (); }    }}

Precautions

1, MyBatis will use log4j log, but open debug mode seems to affect the performance very badly.

2, MyBatis query cache has a very large impact on performance, enabling and not enabling the gap is very large

Note : You must add the cache line to the mapper file, otherwise it will not take effect.

Sample code Download

Download the sample code.

Http://www.cnblogs.com/zhanjindong/p/3397828.html

MyBatis use of demo and cache experience