Mybatis的逆向工程（generator）以及分頁助手（pageHelper）

1.Mybatis的逆向工程（generator）

由表幫咱們來生成到，bean，xml映射文件

　　http://www.mybatis.org/generator/index.html

1.1.引入mybatis-generator的jar包

1.2.建立generator的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
  "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<!-- mysql驅動jar的所在的位置 -->
<generatorConfiguration>
  <classPathEntry location="D:\\jar\\mysql\\mysql-connector-java-5.1.47.jar" />
<!-- 數據源的信息 -->
  <context id="DB2Tables" targetRuntime="MyBatis3">

<!-- 阻止生成文件時自動編寫的備註 -->

<commentGenerator>
  <property name="suppressAllComments " value="true" />
  </commentGenerator>

    <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/mybatis" userId="root" password="root">
    </jdbcConnection>

    <javaTypeResolver >
      <property name="forceBigDecimals" value="false" />
    </javaTypeResolver>
<!-- 生成的實體類所在的位置 -->
    <javaModelGenerator targetPackage="com.zhiyou100.mcl.bean" targetProject=".\src">
      <property name="enableSubPackages" value="true" />
      <property name="trimStrings" value="true" />
    </javaModelGenerator>
<!-- 生成的映射文件所在的位置 -->
    <sqlMapGenerator targetPackage="com.zhiyou100.mcl.mapper"  targetProject=".\src">
      <property name="enableSubPackages" value="true" />
    </sqlMapGenerator>
<!-- 生產的dao包所在的位置 -->
    <javaClientGenerator type="XMLMAPPER" targetPackage="com.zhiyou100.mcl.dao"  targetProject=".\src">
      <property name="enableSubPackages" value="true" />
    </javaClientGenerator>
<!-- 某張表與實體類的對象關係
　　 可複製生成多張表 schema：該表所在的數據庫 tableName：表名 domainObjectName：實體類名 -->
    <table schema="mybatis" tableName="users" domainObjectName="Users" enableCountByExample="false" enableDeleteByExample="false" enableSelectByExample="false" enableUpdateByExample="false">
      <property name="useActualColumnNames" value="true"/>
      <generatedKey column="ID" sqlStatement="DB2" identity="true" />
      <columnOverride column="DATE_FIELD" property="startDate" />
      <ignoreColumn column="FRED" />
      <columnOverride column="LONG_VARCHAR_FIELD" jdbcType="VARCHAR" />
    </table>

  </context>
</generatorConfiguration>

1.3.運行generator

public class TestGenerator { public static void main(String[] args) throws Exception { List<String> warnings = new ArrayList<String>(); boolean overwrite = true; File configFile = new File("generator.xml"); ConfigurationParser cp = new ConfigurationParser(warnings); Configuration config = cp.parseConfiguration(configFile); DefaultShellCallback callback = new DefaultShellCallback(overwrite); MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings); myBatisGenerator.generate(null); }
}

2.Mybatis的分頁助手（pageHelper）

 　　加入相對應的jar包並解壓　

2.1 在 MyBatis 配置 xml 中配置攔截器插件

<!-- plugins在配置文件中的位置必須符合要求，不然會報錯，順序以下: properties?, settings?, typeAliases?, typeHandlers?, objectFactory?,objectWrapperFactory?, plugins?, environments?, databaseIdProvider?, mappers?
-->
<plugins>
    <!-- com.github.pagehelper爲PageHelper類所在包名 -->
    <plugin interceptor="com.github.pagehelper.PageInterceptor">
        <!-- 使用下面的方式配置參數，後面會有全部的參數介紹 -->
        <property name="param1" value="value1"/>
    </plugin>
</plugins>

2.2  在逆向工程幫咱們生成的接口中添加方法

public interface UsersMapper { int deleteByPrimaryKey(Integer id); int insert(Users record); int insertSelective(Users record); Users selectByPrimaryKey(Integer id); int updateByPrimaryKeySelective(Users record); int updateByPrimaryKey(Users record); public List<Users> selectByPageHelper(); }

2.3 映射文件

<?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 namespace="com.zhiyou100.mcl.dao.UsersMapper">
  <resultMap id="BaseResultMap" type="com.zhiyou100.mcl.bean.Users">
    <id column="id" jdbcType="INTEGER" property="id" />
    <result column="NAME" jdbcType="VARCHAR" property="NAME" />
    <result column="sex" jdbcType="VARCHAR" property="sex" />
    <result column="age" jdbcType="INTEGER" property="age" />
  </resultMap>
  <sql id="Base_Column_List"> id, NAME, sex, age </sql>
  <select id="selectByPageHelper" resultType="com.zhiyou100.mcl.bean.Users"> select <include refid="Base_Column_List" /> from users </select>
</mapper>

2.4 測試

@Test void testSelectByPageHelper() { int pageNum=2; int pageSize=3; PageHelper.startPage(pageNum, pageSize); List<Users> list = users.selectByPageHelper(); System.out.println(list); }