public interface UserMapper {
 
    public List<User> findAll() throws IOException;
}

    <!--sql語(yǔ)句抽取-->
    <sql id="selectUser">select * from user</sql>
 
    <select id="findByCondition" parameterType="user" resultType="user">
        <include refid="selectUser"></include>
        <where>
            <if test="id!=0">
                and id=#{id}
            </if>
            <if test="username!=null">
                and username=#{username}
            </if>
            <if test="password!=null">
                and password=#{password}
            </if>
        </where>
    </select>

    <select id="findByIds" parameterType="list" resultType="user">
        <include refid="selectUser"></include>
        <where>
            <foreach collection="list" open="id in(" close=")" item="id" separator=",">
                #{id}
            </foreach>
        </where>
    </select>

public class DateTypeHandler extends BaseTypeHandler<Date> {
    //將java類型 轉(zhuǎn)換成 數(shù)據(jù)庫(kù)需要的類型
    public void setNonNullParameter(PreparedStatement preparedStatement, int i, Date date, JdbcType jdbcType) throws SQLException {
        long time = date.getTime();
        preparedStatement.setLong(i,time);
    }
 
    //將數(shù)據(jù)庫(kù)中類型 轉(zhuǎn)換成java類型
    //String參數(shù)  要轉(zhuǎn)換的字段名稱
    //ResultSet 查詢出的結(jié)果集
    public Date getNullableResult(ResultSet resultSet, String s) throws SQLException {
        //獲得結(jié)果集中需要的數(shù)據(jù)(long) 轉(zhuǎn)換成Date類型 返回
        long aLong = resultSet.getLong(s);
        Date date = new Date(aLong);
        return date;
    }
 
    //將數(shù)據(jù)庫(kù)中類型 轉(zhuǎn)換成java類型
    public Date getNullableResult(ResultSet resultSet, int i) throws SQLException {
        long aLong = resultSet.getLong(i);
        Date date = new Date(aLong);
        return date;
    }
 
    //將數(shù)據(jù)庫(kù)中類型 轉(zhuǎn)換成java類型
    public Date getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
        long aLong = callableStatement.getLong(i);
        Date date = new Date(aLong);
        return date;
    }
}

    <!--注冊(cè)自定義類型處理器-->
    <typeHandlers>
        <typeHandler handler="com.longdi.handler.DateTypeHandler"></typeHandler>
    </typeHandlers>

        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>3.7.5</version>
        </dependency>
        <dependency>
            <groupId>com.github.jsqlparser</groupId>
            <artifactId>jsqlparser</artifactId>
            <version>0.9.1</version>
        </dependency>

    <!--配置分頁(yè)助手插件   配置在mapper之前-->
    <plugins>
        <plugin interceptor="com.github.pagehelper.PageHelper">
            <property name="dialect" value="mysql"></property>
        </plugin>
    </plugins>

        //獲得與分頁(yè)相關(guān)參數(shù)
        PageInfo<User> pageInfo = new PageInfo<User>(userList);
        System.out.println("當(dāng)前頁(yè)："+pageInfo.getPageNum());
        System.out.println("每頁(yè)顯示條數(shù)："+pageInfo.getPageSize());
        System.out.println("總條數(shù)："+pageInfo.getTotal());
        System.out.println("總頁(yè)數(shù)："+pageInfo.getPages());
        System.out.println("上一頁(yè)："+pageInfo.getPrePage());
        System.out.println("下一頁(yè)："+pageInfo.getNextPage());
        System.out.println("是否是第一個(gè)："+pageInfo.isIsFirstPage());
        System.out.println("是否是最后一個(gè)："+pageInfo.isIsLastPage());