Mybatis新手教程之简单入门

package cn.mybatis.po;

public class user {

  private int id;

  private string username;

  private string password;

  private string address;

  private string sex;

  public int getid() {

  return id;

  }

  public string getusername() {

  return username;

  }

  public string getpassword() {

  return password;

  }

  public string getaddress() {

  return address;

  }

  public string getsex() {

  return sex;

  }

  public void setid( int id) {

  this .id = id;

  }

  public void setusername(string username) {

  this .username = username;

  }

  public void setpassword(string password) {

  this .password = password;

  }

  public void setaddress(string address) {

  this .address = address;

  }

  public void setsex(string sex) {

  this .sex = sex;

  }

  @override

  public string tostring() {

  return "user{" +

   "id=" + id +

   ", username='" + username + '\ '' +

   ", password='" + password + '\ '' +

   ", address='" + address + '\ '' +

   ", sex='" + sex + '\ '' +

   '}' ;

  }

}

user实体类

<?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>

  <!--加载资源文件-->

<!-- <properties resource= "jdbc.properties" ></properties>

  <!–settings配置log4j输出日志 –>

  <settings>

  <setting name= "logimpl" value= "log4j" />

  </settings>-->

  <!--typealiases配置包的别名-->

  <!--environments配置了数据库连接，配置了driver、url、username、password属性-->

  <environments default = "development" >

  <environment id= "development" >

   <transactionmanager type= "jdbc" >

   <!--<property name= "" value= "" />-->

   </transactionmanager>

   <datasource type= "pooled" >

   <property name= "driver" value= "com.mysql.jdbc.driver" />

   <property name= "url" value= "jdbc:mysql:///mybatis01" />

   <property name= "username" value= "root" />

   <property name= "password" value= "123" />

   </datasource>

  </environment>

  </environments>

  <!--配置一个sql语句和映射的配置文件-->

  <mappers>

  <mapper resource= "usermapper.xml" />

  </mappers>

</configuration>

mybatis核心配置文件

<?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为根元素，namespace指定了命名空间-->

<mapper namespace= "test" >

  <!--定义一个select查询-->

  <!--parametertype:指定输入参数的类型-->

  <!--#{}表示占位符-->

  <!--#{id}：其中的id表示的就是接受的输入参数，

   参数名称就是id，

  这里指出：如果输入参数是简单类型，#{}中的参数名可以任意设置（value或者其他名称）-->

  <!--resulttype：指定输出类型(即指定输出结果所映射的java对象类型)-->

  <select id= "finduserbyid" parametertype= "int" resulttype= "cn.mybatis.po.user" >

  select * from t_user where id = #{id}

  </select>

</mapper>

usermapper配置文件

package cn.mybatis.first;

import cn.mybatis.po.user;

import org.apache.ibatis.io.resources;

import org.apache.ibatis.session.sqlsession;

import org.apache.ibatis.session.sqlsessionfactory;

import org.apache.ibatis.session.sqlsessionfactorybuilder;

import java.io.ioexception;

import java.io.inputstream;

public class test {

  public user finduserbyid() throws ioexception {

  //得到mybatis配置文件

  string resource = "sqlmapconfig.xml" ;

  //得到配置文件的文件流信息

  inputstream inputstream = resources.getresourceasstream(resource);

  //创建会话工厂 传入mybatis的配置文件信息

  sqlsessionfactory sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);

  //通过会话工厂得到sqlsession

  sqlsession sqlsession = sqlsessionfactory.opensession();

  //通过sqlsession来操作数据库

  //第一个参数就是映射文件中statment的id：namespace +statment的id

  //第二个参数就是制定映射文件中的parametertype类型的参数

  user user = sqlsession.selectone( "test.finduserbyid" , 1 );

  //system.out.println(user);

  //释放会话资源

  try {

   sqlsession.close();

  } catch (exception e) {

   e.printstacktrace();

  }

  return user;

  }

  public static void main(string[] args) {

  // todo auto-generated method stub

  test test = new test();

  try {

   system.out.println(test.finduserbyid());

  } catch (ioexception e) {

   e.printstacktrace();

  }

  }

}

test测试程序

### direct log messages to stdout ###

log4j.rootlogger=debug, stdout

log4j.appender.stdout=org.apache.log4j.consoleappender

log4j.appender.stdout.layout=org.apache.log4j.patternlayout

log4j.appender.stdout.layout.conversionpattern=%5p [%t] - %m%n

log4j.properties

<insert id= "adduser" parametertype= "cn.mybatis.po.user" >

  <!--

  现在需要得到刚刚插入的记录中的主键值,只适用于自增主键的情况

  last_insert_id()

  keyproperty：将查询到的主键值设置到parametertype指定对象中的那个属性

  order：指定相对于insert的顺序

  resulttype：指定映射结果的结果类型

  -->

  <selectkey keyproperty= "id" order= "after" resulttype= "java.lang.integer" >

   select last_insert_id()

  </selectkey>

  insert into t_user(id,username,password,address,sex) values(#{id},#{username},#{password},#{address}, #{sex});

  </insert>

public void inseruser() throws ioexception {

  //得到配置文件的文件流信息

  inputstream inputstream = resources.getresourceasstream( "sqlmapconfig.xml" );

  sqlsessionfactory sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);

  sqlsession sqlsession = sqlsessionfactory.opensession();

  user user = new user( "world" , "1234" , "武汉市" , "男" );

  sqlsession.insert( "test.adduser" ,user);

  system.out.println(user.getid());

  sqlsession测试数据mit();

  //释放会话资源

  try {

   sqlsession.close();

  } catch (exception e) {

   e.printstacktrace();

  }

  }

inseruser函数

<!--

  模糊查询可能会查询多条记录

  resulttype:指定的就是查询结果对应的单条记录类型

  ${}:表示将输入的参数不加任何的修饰，直接作为字符串拼接在sql中

  但是这样直接拼接，容易导致sql注入的隐患

  ${value}中的value表示接受的输入参数，注意如果输入参数是简单类型，其中的形参只能用value

  -->

  <select id= "finduserbyusername" parametertype= "java.lang.string" resulttype= "cn.mybatis.po.user" >

  select * from t_user where username like '%${value}%'

  </select>

public void finduserbyusername() throws ioexception {

  //得到配置文件的文件流信息

  inputstream inputstream = resources.getresourceasstream( "sqlmapconfig.xml" );

  sqlsessionfactory sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);

  sqlsession sqlsession = sqlsessionfactory.opensession();

  list<user> userlist = sqlsession.selectlist( "test.finduserbyusername" , "u" );

  system.out.println(userlist);

  //释放会话资源

  try {

   sqlsession.close();

  } catch (exception e) {

   e.printstacktrace();

  }

  }

findbyusername函数实现

<delete id= "deleteuser" parametertype= "java.lang.integer" >

  delete from t_user where id = #{value}

</delete>

<typealiases>

  <!--针对单个别名的定义-->

  <typealias type= "cn.mybatis.po.user" alias= "user" ></typealias>

  </typealiases>

<select id= "finduserbyidtest" parametertype= "int" resulttype= "user" >

  select * from t_user where id = #{id}

</select>

<typealiases>

  <!--批量别名定义：mybatis在定义别名的时候会自动扫描包中的po类，自动的将别名定义为类名（首字母大写或者小写都可以）-->

  < package name= "cn.mybatis.po" ></ package >

</typealiases>

<mappers>

  <mapper class = "cn.mybatis.mapper.usermapper" ></mapper>

</mappers>

package cn.mybatis.dao;

import cn.mybatis.po.user;

/**

  * 原始dao方式开发：dao接口+dao实现类的方式

  */

public interface userdao {

  //根据id查询信息

  public user finduserbyid( int id) throws exception;

  //添加信息

  public void insertuser(user user) throws exception;

  //删除信息

  public void deleteuser( int id) throws exception;

}

dao接口

package cn.mybatis.dao.daoimpl;

import cn.mybatis.dao.userdao;

import cn.mybatis.po.user;

import org.apache.ibatis.session.sqlsession;

import org.apache.ibatis.session.sqlsessionfactory;

import org.junit.test;

public class userdaoimpl implements userdao {

  //使用构造方法注入sqlsessionfactory

  private sqlsessionfactory sqlsessionfactory;

  public userdaoimpl(sqlsessionfactory sqlsessionfactory) {

   this .sqlsessionfactory = sqlsessionfactory;

  }

  @override

  @test

  public user finduserbyid( int id) throws exception {

   sqlsession sqlsession = sqlsessionfactory.opensession();

   user user = sqlsession.selectone( "test.finduserbyid" ,id);

   sqlsession.close();

   return user;

  }

  @override

  public void insertuser(user user) throws exception {

   sqlsession sqlsession = sqlsessionfactory.opensession();

//  user user1 = new user("test1","123","洪山区","男");

   sqlsession.insert( "test.finduserbyid" ,user);

   sqlsession测试数据mit();

   sqlsession.close();

  }

  @override

  public void deleteuser( int id) throws exception {

   sqlsession sqlsession = sqlsessionfactory.opensession();

   sqlsession.delete( "test.finduserbyid" ,id);

   sqlsession测试数据mit();

   sqlsession.close();

  }

}

dao接口实现类

package cn.mybatis.testdao;

import cn.mybatis.dao.userdao;

import cn.mybatis.dao.daoimpl.userdaoimpl;

import cn.mybatis.po.user;

import org.apache.ibatis.io.resources;

import org.apache.ibatis.session.sqlsessionfactory;

import org.apache.ibatis.session.sqlsessionfactorybuilder;

import org.junit.after;

import org.junit.before;

import org.junit.test;

import java.io.inputstream;

public class userdaoimpltest {

  private sqlsessionfactory sqlsessionfactory;

  @before

  public void setup() throws exception {

   inputstream inputstream = resources.getresourceasstream( "sqlmapconfig.xml" );

   sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);

  }

  @test

  public void testfinduserbyid() throws exception{

   //创建userdao的对象

   userdao userdao = new userdaoimpl(sqlsessionfactory);

   //调用userdao的方法

   user user = userdao.finduserbyid( 1 );

   system.out.println(user );

  }

}

junit测试

<?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为根元素，namespace指定了命名空间-->

<!--在使用mapper代理的方式中，namespace的值应该是mapper接口的路径-->

<mapper namespace= "cn.mybatis.mapper.usermapper" >

  <select id= "finduserbyid" parametertype= "int" resulttype= "cn.mybatis.po.user" >

   select * from t_user where id = #{id}

  </select>

  <delete id= "deleteuser" parametertype= "java.lang.integer" >

   delete from t_user where id = #{value}

  </delete>

</mapper>

mapper.xml配置文件

package cn.mybatis.testmapper;

import cn.mybatis.mapper.usermapper;

import cn.mybatis.po.user;

import org.apache.ibatis.io.resources;

import org.apache.ibatis.session.sqlsession;

import org.apache.ibatis.session.sqlsessionfactory;

import org.apache.ibatis.session.sqlsessionfactorybuilder;

import org.junit.after;

import org.junit.before;

import org.junit.test;

import java.io.inputstream;

public class usermappertest {

  private sqlsessionfactory sqlsessionfactory;

  @before

  public void setup() throws exception {

   inputstream inputstream = resources.getresourceasstream( "sqlmapconfig.xml" );

   sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);

  }

  @test

  public void testfinduserbyid() throws exception{

   sqlsession sqlsession = sqlsessionfactory.opensession();

   //得到usermapper的代理对象

   usermapper usermapper = sqlsession.getmapper(usermapper. class );

   user user = usermapper.finduserbyid( 9 );

   system.out.println(user);

  }

  @test

  public void testdeleteuser() throws exception {

   sqlsession sqlsession = sqlsessionfactory.opensession();

   usermapper usermapper = sqlsession.getmapper(usermapper. class );

   usermapper.deleteuser( 9 );

   sqlsession测试数据mit();

  }

  @after

  public void teardown() throws exception {

  }

}

mapper接口

package cn.mybatis.testmapper;

import cn.mybatis.mapper.usermapper;

import cn.mybatis.po.user;

import org.apache.ibatis.io.resources;

import org.apache.ibatis.session.sqlsession;

import org.apache.ibatis.session.sqlsessionfactory;

import org.apache.ibatis.session.sqlsessionfactorybuilder;

import org.junit.after;

import org.junit.before;

import org.junit.test;

import java.io.inputstream;

public class usermappertest {

  private sqlsessionfactory sqlsessionfactory;

  @before

  public void setup() throws exception {

   inputstream inputstream = resources.getresourceasstream( "sqlmapconfig.xml" );

   sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);

  }

  @test

  public void testfinduserbyid() throws exception{

   sqlsession sqlsession = sqlsessionfactory.opensession();

   //得到usermapper的代理对象

   usermapper usermapper = sqlsession.getmapper(usermapper. class );

   user user = usermapper.finduserbyid( 8 );

   system.out.println(user);

  }

  @test

  public void testdeleteuser() throws exception {

   sqlsession sqlsession = sqlsessionfactory.opensession();

   usermapper usermapper = sqlsession.getmapper(usermapper. class );

   usermapper.deleteuser( 8 );

  }

  @after

  public void teardown() throws exception {

  }

}

junit测试