Java中使用递归算法实现子级架构的查询

青旅半醒 2023-10-18 20:01 18阅读 0赞

## 场景 ##

在实现企业架构管理时采用树形结构。如图：

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70][]

现在要根据传递的id属性查询其有多少个子级架构。

注：如果A的id是B的pid，那么A就是B的父级。

## 实现 ##

递归函数如下：

public void selectChild(List<Long> ids){
            //用来存取调用自身递归时的参数
            List<Long> temp= new ArrayList<Long>();
            //查询数据库中对应id的实体类
            List<SysEnterpriseOrg> sysEnterpriseOrgList = new ArrayList<SysEnterpriseOrg>();
            //遍历传递过来的参数ids
            for (Long id :ids) {
                //查询子级架构
                //此处使用mybaatisPlus的条件构造器，查询pid等于id的对象
                QueryWrapper<SysEnterpriseOrg> sysEnterpriseOrgChildQueryWrapper = new QueryWrapper<SysEnterpriseOrg>();
                sysEnterpriseOrgChildQueryWrapper.eq("pid",id.toString());
                //查询结果返会一个list
                sysEnterpriseOrgList= sysEnterpriseOrgMapper.selectList(sysEnterpriseOrgChildQueryWrapper);
                //遍历list获取符合条件的对象的id值，一份存到temp中用作递归的参数，并存到全局变量中用来获取所有符合条件的id
                for (SysEnterpriseOrg s:sysEnterpriseOrgList) {
                    temp.add(s.getId());
                    result.add(s.getId());
                }
            }
           if(temp.size()!=0&&temp!=null){
                selectChild(temp);
            }
    
        }

单元测试调用示例:

package com.ws.test.common;
    
    import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
    import com.ws.sys.entity.SysEnterpriseOrg;
    import com.ws.sys.mapper.SysEnterpriseOrgMapper;
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    import org.springframework.test.context.web.WebAppConfiguration;
    
    import java.util.ArrayList;
    import java.util.List;
    
    
    /**
     * Created by HAOHAO on 2019/6/18.
     */
    @RunWith(SpringJUnit4ClassRunner.class)
    @SpringBootTest
    @WebAppConfiguration
    public class diguiTest  {
        @Autowired
        private SysEnterpriseOrgMapper sysEnterpriseOrgMapper;
        List<Long> result = new ArrayList<Long>();
        @Test
        public void test(){
            List<Long> canshu = new ArrayList<Long>();
            canshu.add(1l);
            selectChild(canshu);
            for (Long s :result
                 ) {
                System.out.print(s);
            }
        }
    
        public void selectChild(List<Long> ids){
            //用来存取调用自身递归时的参数
            List<Long> temp= new ArrayList<Long>();
            //查询数据库中对应id的实体类
            List<SysEnterpriseOrg> sysEnterpriseOrgList = new ArrayList<SysEnterpriseOrg>();
            //遍历传递过来的参数ids
            for (Long id :ids) {
                //查询子级架构
                //此处使用mybaatisPlus的条件构造器，查询pid等于id的对象
                QueryWrapper<SysEnterpriseOrg> sysEnterpriseOrgChildQueryWrapper = new QueryWrapper<SysEnterpriseOrg>();
                sysEnterpriseOrgChildQueryWrapper.eq("pid",id.toString());
                //查询结果返会一个list
                sysEnterpriseOrgList= sysEnterpriseOrgMapper.selectList(sysEnterpriseOrgChildQueryWrapper);
                //遍历list获取符合条件的对象的id值，一份存到temp中用作递归的参数，并存到全局变量中用来获取所有符合条件的id
                for (SysEnterpriseOrg s:sysEnterpriseOrgList) {
                    temp.add(s.getId());
                    result.add(s.getId());
                }
            }
            if(temp.size()!=0&&temp!=null){
                selectChild(temp);
            }
    
        }
    }

##     ##

[Image 1]: 
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