Data Access 之 MyBatis（八）- MyBatis 通用 Mapper（Part B）（下）

Example porscheExample = new Example(Porsche.class);
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WHERE (por_id > 1 and por_stock > 20) OR ( por_price < 1000000 and por_stock > 20)
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List<Porsche> getPorschesByPriceAndStock(Example porscheExample);
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@Override
public List<Porsche> getPorschesByPriceAndStock(Example porscheExample) {
    return porscheMapper.selectByExample(porscheExample);
}
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@Test
public void getPorscheByPriceAndStock(){
    Example porscheExample = new Example(Porsche.class);
    // WHERE (por_id > 1 and por_stock > 20) OR ( por_price < 1000000 and por_stock > 20)
    // 创建两个查询条件，WHERE关键字后面的两个括号分别对应两个查询条件
    Example.Criteria criteria1 = porscheExample.createCriteria();
    Example.Criteria criteria2 = porscheExample.createCriteria();
    // 设置两个查询条件
    criteria1.andGreaterThan("porId",1)
            .andGreaterThan("porStock",20);
    criteria2.andLessThan("porPrice",1000000d)
            .andGreaterThan("porStock",20);
    // 通过OR连接查询条件1--criteria1和查询条件2--criteria2
    // porschExample就相当于select 字段名 from 表明 WHERE criteria 1
    // 只需要调用or方法将criteria2连接上，就构成了完成的SQL语句
    // select 字段名 from 表明 WHERE (criteria1) OR (criteria2)
    porscheExample.or(criteria2);
    List<Porsche> porscheList = porscheService.getPorschesByPriceAndStock(porscheExample);
    for (Porsche porsche : porscheList) {
        System.out.println("查询到的内容为：" + porsche);
    }
}
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porscheExample.setDistinct(true);
porscheExample.orderBy("porPrice").asc().orderBy("porName").desc();
porscheExample.selectProperties("porName","porPrice");
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// 根据example条件和RowBounds进行分页查询
List<T> selectByExampleAndRowBounds(Object example, RowBounds rowBounds);
// 根据实体属性和RowBounds进行分页查询
List<T> selectByRowBounds(T record, RowBounds rowBounds);
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List<Porsche> getPorschesByRowBounds(Porsche record, RowBounds rowBounds);
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@Override
public List<Porsche> getPorschesByRowBounds(Porsche record, RowBounds rowBounds) {
    return porscheMapper.selectByRowBounds(record,rowBounds);
}
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@Test
public void getPorschesByRowBounds(){
    int pageNo = 2;
    int pageSize = 3;
    int index = (pageNo - 1) * pageSize;
    RowBounds rowBounds = new RowBounds(index, pageSize);
    List<Porsche> porscheList = porscheService.getPorschesByRowBounds(null, rowBounds);
    for (Porsche porsche : porscheList) {
        System.out.println("查询到的内容为：" + porsche);
    }
}
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<dependency>
    <groupId>tk.mybatis</groupId>
    <artifactId>mapper-generator</artifactId>
    <version>1.0.0</version>
</dependency>
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<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <properties resource="db.properties"/>
    <context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat">
        <property name="beginningDelimiter" value="`"/>
        <property name="endingDelimiter" value="`"/>
        <!--通用Mapper的MBG插件-->
        <plugin type="tk.mybatis.mapper.generator.MapperPlugin">
            <property name="mappers" value="tk.mybatis.mapper.common.Mapper"/>
            <property name="caseSensitive" value="true"/>
        </plugin>
        <jdbcConnection driverClass="${jdbc_driver}"
                        connectionURL="${jdbc_url}"
                        userId="${jdbc_username}"
                        password="${jdbc_password}">
        </jdbcConnection>
        <javaModelGenerator targetPackage="com.citi.entity"
                            targetProject="./src/main/java"/>
        <sqlMapGenerator targetPackage="mappers"
                         targetProject="./src/main/resources"/>
        <javaClientGenerator targetPackage="com.citi.mapper"
                             targetProject="./src/main/java"
                             type="XMLMAPPER"/>
        <!--tableName="%"表示所有表都参与逆向工程-->
        <table tableName="t_teacher" domainObjectName="Teacher">
            <generatedKey column="id" sqlStatement="Mysql"/>
        </table>
    </context>
</generatorConfiguration>
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<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.3.7</version>
            <configuration>
                <configurationFile>
                    ${basedir}/src/main/resources/generatorConfig.xml
                </configurationFile>
                <overwrite>true</overwrite>
                <verbose>true</verbose>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>8.0.16</version>
                </dependency>
                <dependency>
                    <groupId>tk.mybatis</groupId>
                    <artifactId>mapper</artifactId>
                    <version>4.0.0</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
</build>
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@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:application.xml")
public class TeacherMapperTest {
    @Resource
    private TeacherMapper teacherMapper;
    @Test
    public void selectAll(){
        List<Teacher> teachers = teacherMapper.selectAll();
        for (Teacher teacher : teachers) {
            System.out.println("查询到的内容为:" + teacher.getTeacherName());
        }
    }
}
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