java后台树形结构展示---懒加载

一、数据库设计

二、实体类：entity

import com.joyoung.cloud.security.common.validatedGroup.Add;
import com.joyoung.cloud.security.common.validatedGroup.Modify;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import lombok.experimental.Accessors;

import javax.persistence.Id;
import javax.persistence.Transient;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Null;
import javax.validation.constraints.Pattern;
import java.io.Serializable;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;

/**
 * 公司表(SysCompany)实体类
 *
 * @author yangyuwei
 * @since 2019-06-06 13:45:23
 */
@ApiModel(value = "公司类")
@Data
@Accessors(chain = true)
public class SysCompany implements Serializable {
    private static final long serialVersionUID = 600959061181555399L;
    @ApiModelProperty(value = "主键Id")
    @Id
    @Null(message = "{add_id}", groups = {Add.class})
    @NotNull(message = "{modify_id}", groups = {Modify.class})
    private String id;
    //上级公司id
    @ApiModelProperty(value = "父Id")
    private String parentId;
    //公司名称
    @ApiModelProperty(value = "公司名称")
    @NotBlank(message = "{name_null}")
    @Pattern(regexp = "^[\\s\\S]{1,20}$", message = "{name_rule}")
    private String coName;
    //公司简称
    @ApiModelProperty(value = "公司简称")
    private String coAbbr;
    //公司编号
    @ApiModelProperty(value = "公司编号")
    private String coCode;
    //公司地址
    @ApiModelProperty(value = "公司地址")
    private String coAddr;
    //邮编
    @ApiModelProperty(value = "邮编")
    @Pattern(regexp = "^$|[0-9]{6}$", message = "{zipCode_error}")
    private String zipCode;
    //法人名称
    @ApiModelProperty(value = "法人名称")
    private String legalName;
    //法定代表人
    @ApiModelProperty(value = "法定代表人")
    private String legalRep;
    //税号
    @ApiModelProperty(value = "税号")
    private String taxId;
    //电话号码("XXX-XXXXXXX"、"XXXX-XXXXXXXX"、"XXX-XXXXXXX"、"XXX-XXXXXXXX"、"XXXXXXX"和"XXXXXXXX)
//    @Pattern(regexp = "^(\\(\\d{3,4}\\)|\\d{3,4}-|\\s)?\\d{7,14}$", message = "请输入正确的电话号码")
    @ApiModelProperty(value = "电话号码")
    private String tel;
    //开户银行名称
    @ApiModelProperty(value ="开户银行名称")
    private String bankName;
    //开户银行账号
    @ApiModelProperty(value = "开户银行账号")
    private String bankAcct;
    //创建人id
    private String crtUser;
    //创建人名称
    private String crtName;
    //创建时间
    private Date crtTime;
    //最后修改人id
    private String updUser;
    //最后修改人名称
    private String updName;
    //最后修改时间
    private Date updTime;
    //备注
    private String remark;
    //逻辑删除标识：1=删除；0=未删除
    private Integer delFlag;

    private String attr1;

    private String attr2;

    private String attr3;

    /*****************************以下为添加字段*********************************/
    @Transient
    private Boolean hasChecked;
    @Transient
    private Boolean hasChildren;
    @Transient
    private List<SysCompany> children = new LinkedList<SysCompany>();

}

三、controller

@ApiOperation(value = "懒加载查询列表")
@GetMapping("/children")
public List<SysCompany> getChildren(SysCompany sysCompany) {
    return service.getChildren(sysCompany);
}

四、service

@Override
public List<SysCompany> getChildren(SysCompany sysCompany) {
    List<SysCompany> companyList = dao.selectCompanyInfo(sysCompany);
    if (StringUtils.isNotBlank(sysCompany.getCoName())) {
        return getTree(sysCompany);
    }
    return companyList;
}

/**
这里一般将此方法放在entity里面
*/

private List<SysCompany> getTree(SysCompany sysCompany) {
    Map<String, SysCompany> map = dao.selectByCompany(sysCompany);
    List<SysCompany> tree = new ArrayList<>();
    map.forEach((id, obj) -> {
        if (map.containsKey(obj.getParentId())) {
            map.get(obj.getParentId()).getChildren().add(obj);
        } else {
            tree.add(obj);
        }
    });
    return tree;
}

五、dao

public List<SysCompany> selectCompanyInfo(SysCompany sysCompany);

六、mapper

<sql id="sys_param">
    c.id,
    c.parent_id,
    c.co_name,
    c.co_abbr,
    c.co_code,
    c.co_addr,
    c.zip_code,
    c.legal_name,
    c.legal_rep,
    c.tax_id,
    c.tel,
    c.bank_name,
    c.bank_acct,
    c.crt_user,
    c.crt_name,
    c.crt_time,
    c.upd_user,
    c.upd_name,
    c.upd_time,
    c.remark,
    c.del_flag
</sql>
<select id="selectCompanyInfo" resultMap="SysCompanyMap"
        parameterType="com.joyoung.cloud.security.common.entity.admin.SysCompany">
    SELECT
    <include refid="sys_param"/>,EXISTS (SELECT 1 from sys_company sc where sc.parent_id=c.id and sc.del_flag=0) as
    hasChildren
    FROM
    sys_company c
    WHERE
    c.del_flag = 0
    <if test="coName!=null">
        and c.co_name like concat ('%',#{coName},'%')
    </if>
    <if test="parentId !=null and parentId !=''">
        and c.parent_id = #{parentId}
    </if>
    <if test="parentId == null || parentId == ''">
        and c.parent_id is null
    </if>
</select>