springboot2.0 使用aop实现PageHelper分页

参考：

https://blog.csdn.net/qq_24076135/article/details/85212081

https://www.jianshu.com/p/036d31ae77d3

一、编写分页实体类

/**
 * 此类用于返回分页结果集
 * @param <T>
 */
public class PageResult<T> {

    private Long total;
    private Integer totalPage;
    private List<T> rows;

    public PageResult() {
    }

    public PageResult(List<T> rows) {
        this.rows = rows;
        PageInfo pageInfo = new PageInfo(rows);
        this.total = pageInfo.getTotal();
    }

    public PageResult(Long total, List<T> rows) {
        this.total = total;
        this.rows = rows;
    }

    public PageResult(Long total, Integer totalPage, List<T> rows) {
        this.total = total;
        this.totalPage = totalPage;
        this.rows = rows;
    }

    public Long getTotal() {
        return total;
    }

    public void setTotal(Long total) {
        this.total = total;
    }

    public Integer getTotalPage() {
        return totalPage;
    }

    public void setTotalPage(Integer totalPage) {
        this.totalPage = totalPage;
    }

    public List<T> getRows() {
        return rows;
    }

    public void setRows(List<T> rows) {
        this.rows = rows;
    }
}

二、未使用aop时，编写service层

 public PageResult<Device> selectList(Map<String,Object> map) {
        this.page = Integer.parseInt((String) map.get("page"));
        this.size = Integer.parseInt((String) map.get("size"));
        PageHelper.startPage(this.page,this.size);
        List<Device> devices = this.deviceMapper.selectList(map);
        PageInfo<Device> pageInfo = new PageInfo<>(devices);
        return new PageResult<>(pageInfo.getTotal(),pageInfo.getList());
    }

使用aop后：

    public PageResult<Device> selectList(Map<String,Object> map) {
        List<Device> devices = this.deviceMapper.selectList(map);
        return new PageResult<Device>(devices);
    }

分离的部分：

        this.page = Integer.parseInt((String) map.get("page"));
        this.size = Integer.parseInt((String) map.get("size"));
        PageHelper.startPage(this.page,this.size);

　　　　 PageInfo<Device> pageInfo = new PageInfo<>(devices);

三、dao层(即mapper)

public interface DeviceMapper {

    public List<Device> selectList(Map<String,Object> map);
}

四、Controller层（有待优化）

    @GetMapping("/list")
    public ResponseEntity<PageResult<Device>> selectList(@RequestParam Map<String,Object> map){
        PageResult<Device> result = this.deviceService.selectList(map);
        if(CollectionUtils.isEmpty(result.getRows())){
            result = null;
            return ResponseEntity.ok(result);
        }
        return ResponseEntity.ok(result);
    }

五、重点：编写aop切面类

@Component
@Aspect
@Slf4j
public class PageHelperAspect {

    @Pointcut("execution(* cn.factory.service.impl.*.*(..))")
    public void pageFunction(){};

    @Around("pageFunction()")
    public Object serviceImplAop(ProceedingJoinPoint pjp){
        try {
            log.info("进入pagehelper aop");

            //获取连接点方法运行时的入参列表
            Object[] args = pjp.getArgs();

            Map<String,Object> map = (Map<String,Object>)args[0];

            // 获取连接点的方法签名对象
            Signature signature = pjp.getSignature();

            // 获取连接点所在的类的对象（实例）
            Object target = pjp.getTarget();

            PageHelper.startPage(Integer.parseInt((String) map.get("page")),Integer.parseInt((String) map.get("size")));

            log.info("方法[{}]开始执行.....",signature.getName());
            // 调用业务层方法，执行sql语句
            Object object = pjp.proceed();
            log.info("方法[{}]执行结束....",signature.getName());
//            if (object instanceof List) {
//                List objList = (List) object;
//                PageInfo pageInfo = new PageInfo<>(objList);
//                return pageInfo;
//            }
            return object;
        } catch (Throwable throwable) {
            log.info("pageInfo aop执行失败....");
            throw new RuntimeException(throwable);
        } finally {
            log.info("serviceImplAop执行结束.....");
        }
    }
}

 附上所需的依赖：如果依赖版本不匹配或者错误可能会出现net.sf.jsqlparser.statement.select.PlainSelect.getGroupByColumnReferences()Ljava/util/List;] with root cause此类错误

<!-- web启动器 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- eureka客户端 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- mybatis的启动器 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <!-- 通用mapper启动器 -->
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper-spring-boot-starter</artifactId>
        </dependency>

        <!-- mybatis的分页插件 -->
        <!--pageHelper基本依赖 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.1.2</version>
        </dependency>
        <!-- 不加这两个依赖分页不会成功 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-autoconfigure</artifactId>
            <version>1.2.5</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.5</version>
        </dependency>
        <!-- jdbc启动器 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!-- mysql驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- springboot检测服务启动器 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <!--druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.19</version>
        </dependency>

        <!-- alibaba的druid数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.0</version>
        </dependency>
        <!--加密-->
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
        </dependency>