Mybatis-plus配置分页插件返回统一结果集-Java开发

本文主要介绍了Mybatis-plus配置分页插件返回统一结果集，文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值，需要的朋友们下面随着小编来一起学习学习吧

一、MyBatisPlusConfig中配置分页插件

   /**
     * 配置分页插件
     * @return page
     */
    @Bean
    public PaginationInterceptor paginationInterceptor(){
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        // 开启 count 的 join 优化,只针对部分 left join
        paginationInterceptor.setCountSqlParser(new JsqlParserCountOptimize(true));
        return paginationInterceptor;
    }

1. 分页实现的原理

Mybatis-plus分页插件使用的是IPage进行分页。IPage内部原理是基于拦截器，拦截的是方法以及方法中的参数。判断是否是查询操作，如果是查询操作，才会进入分页的处理逻辑。进入分页逻辑处理后，拦截器会通过反射获取该方法的参数进行判断是否存在IPage对象的实现类。如果不存在则不进行分页，存在则将该参数赋值给IPage对象，然后进行拼接sql的处理完成分页操作。

二、统一结果集

1. 创建返回码定义类

public class ResultCode {

    /**
     * 成功
     **/
    public final static int OK = 20000;
    /**
     * 失败
     **/
    public final static int ERROR = 20001;
    /**
     * 用户名或密码错误
     **/
    public final static int LOGIN_ERROR = 20002;
    /**
     * 权限不足
     **/
    public final static int ACCESS_ERROR = 20003;
    /**
     * 远程调用失败
     **/
    public final static int REMOTE_ERROR = 20004;
    /**
     * 重复操作
     **/
    public final static int REPEAT_ERROR = 20005;
}

2. 创建结果集类

@Data
@ApiModel(value = "全局统一返回结果")
public class R implements Serializable {

    public final static String OK_MSG = "请求成功";
    public final static String FAIL_MSG = "请求失败";

    @ApiModelProperty(value = "是否成功")
    private boolean success;

    @ApiModelProperty(value = "返回码")
    private Integer code;

    @ApiModelProperty(value = "返回消息")
    private String message;

    @ApiModelProperty(value = "返回数据")
    private Object data;

    @ApiModelProperty(value = "总条数")
    private Long total;

    @ApiModelProperty(value = "分页信息")
    private PageInfo pageInfo;

    @Data
    public static class PageInfo {

        @ApiModelProperty("当前页")
        protected int currentPage;
        @ApiModelProperty("页大小")
        protected int pageSize;
        @ApiModelProperty("总记录数")
        protected long totalCount;
        @ApiModelProperty("总页数")
        protected long totalPage;

        public PageInfo() {
        }

        @ConstructorProperties({"currentPage", "pageSize", "totalCount", "totalPage"})
        public PageInfo(int currentPage, int pageSize, long totalCount, long totalPage) {
            this.currentPage = currentPage;
            this.pageSize = pageSize;
            this.totalCount = totalCount;
            this.totalPage = totalPage;
        }
    }

    private R(){}

    private R(int code, String msg, Object data) {
        this.code = code;
        this.message = msg;
        if (data instanceof Page<?>) {
            Page<?> page = (Page<?>) data;
            this.total = page.getTotal();
            this.data = page.getRecords();
            this.pageInfo = new PageInfo((int)page.getCurrent(), (int)page.getSize(), page.getTotal(), page.getPages());
        } else {
            this.data = data;
        }
    }

    public static R ok(){
        R r = new R();
        r.setSuccess(true);
        r.setCode(ResultCode.OK);
        r.setMessage("成功");
        return r;
    }
    public static R ok(Object data) {
        return new R(ResultCode.OK, OK_MSG, data);
    }

    public static R ok(String msg, Object data) {
        return new R(ResultCode.OK, msg, data);
    }

    public static R error(){
        R r = new R();
        r.setSuccess(false);
        r.setCode(ResultCode.ERROR);
        r.setMessage("失败");
        return r;
    }

    public static R error(String msg) {
        return new R(ResultCode.ERROR, msg, null);
    }

    public static R error(int errorCode, String msg) {
        return new R(errorCode, msg, null);
    }


    public R message(String message){
        this.setMessage(message);
        return this;
    }

    public R code(Integer code){
        this.setCode(code);
        return this;
    }

    public R data(Object data){
        this.setData(data);
        return this;
    }

}
复制代码

三、编写分页接口

1. 先编写查询类

代码如下：

@Data
public class MemberQueryVo extends BasePageEntity{

    @ApiModelProperty(value = "用户名")
    private String userName;
}

2. service层

先定义一个查询分页的接口，在实现类里做相关处理

@Service
public class MemberServiceImpl extends ServiceImpl<MemberMapper, Member> implements MemberService {

    @Override
    public IPage<Member> listMemberPage(MemberQueryVo queryVo) {
        IPage<Member> page = new Page<>(queryVo.getCurrentPage(),queryVo.getCurrentPage());
        //条件查询
        LambdaQueryWrapper<Member> queryWrapper = new LambdaQueryWrapper<Member>();

        if (StringUtils.isNotBlank(queryVo.getUserName())) {
            queryWrapper.like(Member::getUserName, queryVo.getUserName());
        }

        return baseMapper.selectPage(page,queryWrapper);
    }
}

3. controller层

编写分页接口，代码如下：

    @ApiOperation(value = "分页用户列表")
    @GetMapping(value = "/getPage")
    public R listPage(MemberQueryVo queryVo){
        IPage<Member> page = memberService.listMemberPage(queryVo);
        return R.ok(page);
    }