java商品类的无限递归展示

java商品类或者雇员的的无限递归展示

20170630

java树的无限层级递归，也可以理解为商品类的无限层级递归，其实思想是一样的，
但是在实际项目中，这里的数据源文件可能是从数据库中提取

给定一个文件，文件中数据为下面所示：

liu,108391,123457zhao,123457,123139xin,610123,123457hu,507123,123457zhang, 123139,            xu,123422,123457qian,123456,123422

数据表示为： employeeName,employeeId, employee boss id.

注意: 1.有些人没有boss id ; 2.注意空格的处理

问题：给定一个人的,打印出他的下属ID的层级结构

import java.io.BufferedReader;import java.io.File;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.util.ArrayList;import java.util.HashMap;import java.util.HashSet;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Set;class Employee{    public Employee(String name, Integer id, Integer parentId) {        super();        this.name = name;        this.id = id;        this.parentId = parentId;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Integer getId() {        return id;    }    @Override    public String toString() {        return "Employee [name=" + name + ", id=" + id + ", parentId="                + parentId + "]";    }    public void setId(Integer id) {        this.id = id;    }    public Integer getParentId() {        return parentId;    }    public void setParentId(Integer parentId) {        this.parentId = parentId;    }    private String name;    private Integer id;    private Integer parentId;}public class FileReaderTest {    public static final Set<Employee> employeeSetAll= new HashSet();      public static final String SPACE = " ";    public static void readFileTest(String fileName,Set<Employee> employeeSet) throws IOException{        int count                           = 0;        BufferedReader br                   = null;        FileReader fileReader               = new FileReader(fileName);        if(fileReader != null){            try (BufferedReader br1 = new BufferedReader(fileReader)) {                String line;                while ((line = br1.readLine()) != null) {                    String [] dataArray = line.split(",");                    Employee e = null;                    if(dataArray.length >= 3){                         e = new Employee(dataArray[0],Integer.parseInt(dataArray[1].trim()),Integer.parseInt(dataArray[2].trim()));                    }else{                        e = new Employee(dataArray[0],Integer.parseInt(dataArray[1].trim()),null);                    }                    employeeSet.add(e);                }            }        }else{            System.out.println("can not find the file");        }    }    /**     * ????????????id???     * @return     */    public static  Set<Employee> findChildEmployee(Set<Employee> employeeSet,Integer id,int level){        Iterator<Employee> it = employeeSetAll.iterator();        List<Employee> employeeList = new ArrayList<Employee>();        while(it.hasNext()){            Employee e = it.next();            Integer parentIdValue= e.getParentId();            if(id.equals(e.getParentId())){                employeeList.add(e);            }            if(e.getId().intValue()==id.intValue()){                employeeSet.add(e);            }        }        for(Employee e:employeeList){            for(int i=0;i<level;i++){                System.out.print(SPACE);            }            System.out.println(e.getId());            findChildEmployee(employeeSet,e.getId(),level+1);        }        return  employeeSet;    }    public static void main(String[] args) {            try {            readFileTest("data.txt",employeeSetAll);        } catch (IOException e) {            e.printStackTrace();        }        for(Employee e : employeeSetAll){            System.out.println(e);        }        Set<Employee> employeeSet= new HashSet();        StringBuffer sb = new StringBuffer();        findChildEmployee(employeeSet,123139,0);    }}

在happymmall也使用了类似的层级结构，但是数据源是从MySQl中获取的。