MyBatis Framework Introduction (1)

MyBatis Introduction:

MyBatis is a Java-based persistence layer framework that separates SQL statements from code and is a manifestation of configuration-oriented programming. MyBatis can well support mapping of replicated objects. Apply dynamic SQL technology to avoid assembling SQL statements.

MyBatis Download:

Http://mybatis.github.io/2014/10/11/mybatis-3.2.8-released.html

In the project to the order of the package:

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To import the results in the project:

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Post-Import configuration log:

MyBatis SQL statement output is done through the log, so you need to configure the log: The log output level is debug

Log files can be downloaded and modified from the Web:

Log4j.rootlogger=debug, Console #Console log4j.appender.console=org.apache.log4j.consoleappender Log4j.appender.console.layout=org.apache.log4j.patternlayout log4j.appender.console.layout.conversionpattern=%d [%t]%-5p [%c]-%m%n log4j.logger.java.sql.resultset=info log4j.logger.org.apache=info Log4j.logger.java.sql.Connect Ion=debug Log4j.logger.java.sql.statement=debug Log4j.logger.java.sql.preparedstatement=debug

MyBatis Workflow:

• Read Basic configuration file: Information about the source database

• Build Sqlsessionfactory: is a sqlsession project that is used to establish a session between the databases

• Build sqlsession: Execute SQL statement

• Call MyBatis to provide an API

• Querying the Map configuration

• return Result:

• Close sqlsession
  

Basic configuration file:

Contains two parts:

• Connect Database related Information

• Path location of the map configuration file
  

<?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>  < environments default= "Development" >    <environment id= "development" >       <transactionmanager type= "JDBC" >       </transactionmanager>      <datasource type= "POOLED" >    //whether to use connection pooling         <property name= "Driver"  value= "Com.mysql.jdbc.Driver"/>        <property name = "url"  value= "Jdbc:mysql://localhost:3306/jikebook"/>         <property name= "username"  value= "root"/>  &Nbsp;     <property name= "Password"  value= "* * *"/>       </datasource>    </environment>  </environments >  <mappers>    <mapper resource= "Jike/book/map/jikeUser.xml"/ >  </mappers></configuration>

This file can be downloaded and modified from the Internet

There are several types of map configuration files:

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Map file:

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The ID here is unique. Resulttype is the return value type. ParameterType is a parameter type

Database Connection code:

String resource = "Jike/book/map/mybatisconfig.xml"; The path of the basic configuration reader reader = null; Stream object Sqlsession session; Execute sqltry {reader = Resources.getresourceasreader (Resource),} catch (IOException e) {//TODO auto-generated catch Blocke . Printstacktrace ();} Sqlsessionfactory sqlmapper = new Sqlsessionfactorybuilder (). build (reader); session = Sqlmapper.opensession (); ...... session.close ();

This piece of code is generic

Use a project to illustrate MyBatis's content.

The entire project was established as follows:

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New database: Jikebook

Add table Jikeuser to the database:

create database /*!32312 if not exists*/' Jikebook '  /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_bin */; use  ' Jikebook ';/*table structure for table  ' Jikeuser '  */drop table if  EXISTS  ' Jikeuser '; create table  ' Jikeuser '   (   ' id '  int (one)  not null auto_increment,    ' UserName '  varchar ( COLLATE utf8_bin DEFAULT NULL,   ') Password '  varchar ( collate utf8_bin default null,  primary key)   (' id '))  engine=innodb auto_increment=2 default charset=utf8 collate=utf8_bin;/* data for the table  ' jikeuser '  */insert  into  ' jikeuser ' (' id ', ' userName ', ' password ')  values  (1, ' Hello everyone ', NULL); 

Create a new Jikeuser in the Pojo package, add code: Where the variable is consistent with the variable name in the database

Package Jike.book.pojo;public class Jikeuser {private int id;private string username;private string password;public int ge TId () {return ID;} public void setId (int id) {this.id = ID;} Public String GetUserName () {return userName;} public void Setusername (String userName) {this.username = UserName;} Public String GetPassword () {return password;} public void SetPassword (String password) {this.password = password;}}

config mybatisconfig.xml:

<?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>  < environments default= "Development" >    <environment id= "development" >       <transactionmanager type= "JDBC" >       </transactionmanager>      <datasource type= "POOLED" >         <property name= "Driver"  value= " Com.mysql.jdbc.Driver "/>        <property name=" url "  Value= "Jdbc:mysql://localhost:3306/jikebook"/>        <property  name= "username"  value= "root"/>      &nbsP; <property name= "password"  value= "123"/>      </ datasource>    </environment>  </environments>  < Mappers>    <mapper resource= "Jike/book/map/jikeuser.xml"/>  </ Mappers></configuration>

To add a map file:

Jike/book/map/jikeuser.xml

<?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" ><mapp ER namespace= "/" > <select id= "FindByID" parametertype= "int" resulttype= "Jike.book.pojo.JiKeUser" > select * From Jikeuser where Id=#{id} </select></mapper>

To create a new test class:

package jike.book.test;import java.io.ioexception;import java.io.reader;import  jike.book.pojo.jikeuser;import org.apache.ibatis.io.resources;import  org.apache.ibatis.session.sqlsession;import org.apache.ibatis.session.sqlsessionfactory;import  Org.apache.ibatis.session.sqlsessionfactorybuilder;public class testhello {public static  void main (String[] args)  {// TODO Auto-generated method stub//  Connect database string resource =  "Jike/book/map/mybatisconfig.xml"; reader reader = null; Sqlsession session;try {reader = resources.getresourceasreader (Resource);}  catch  (ioexception e)  {// TODO Auto-generated catch  Blocke.printstacktrace ();} Sqlsessionfactory sqlmapper = new sqlsessionfactorybuilder (). build (reader); session =  sqlmapper.opensession ();//jikeuser temp = session. SelectOne ("FindByID",  1); //  The first parameter is the ID of the SQL statement, consistent with the ID configured in the previous XML.   The second is the IdSystem.out.println (Temp.getusername ()) recorded in the database; Session.close ();}}

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MyBatis Framework Introduction (1)