場景：需要把考生進行分類處理。已知考生在一個List容器中。考生有所屬機構。

分析：如何才能把List中的考生分類呢？有考生id，有機構id，有機構名稱，而且我應該按照機構id進行分類。

思考：按照什麼進行分類處理？考生所屬機構。建立一個CandidateOrg類，類中擁有orgId,orgName,candidateIdList。

如何儲存：一個CandidateOrg物件是一個組織機構，這個組織機構中擁有一個List屬性，而這個candidateIdList屬性，就儲存當前機構下的所有考生id。

需要的類：Candidate,CandidateOrg。

public class Candidate{
private String orgId;//我的目的是以這個orgId分類
private String orgName;
private String candidateId;

public Candidate(){

}

public Candidate(String orgId, String candidateId, String orgName) {
super();
this.candidateId = candidateId;
this.orgId = orgId;
this.orgName = orgName;
}


public String getCandidateId() {
return candidateId;
}

public void setCandidateId(String candidateId) {
this.candidateId = candidateId;
}

public String getOrgId() {
return orgId;
}

public void setOrgId(String orgId) {
this.orgId = orgId;
}

public String getOrgName() {
return orgName;
}

public void setOrgName(String orgName) {
this.orgName = orgName;

}

}

public class CandidateOrg{
private String orgId;
private String orgName;
private List<String> candidateIdList;

public CandidateOrg() {

}

public CandidateOrg(String orgId, String orgName, List<String> candidateIdList) {
super();
this.orgId = orgId;
this.orgName = orgName;
this.candidateIdList = candidateIdList;
}

public String getOrgId() {
return orgId;
}

public void setOrgId(String orgId) {
this.orgId = orgId;
}

public String getOrgName() {
return orgName;
}

public void setOrgName(String orgName) {
this.orgName = orgName;
}

public List<String> getCandidateIdList() {
return candidateIdList;
}

public void setCandidateIdList(List<String> candidateIdList) {
this.candidateIdList = candidateIdList;

}

}

public class TestCandidateOrg {
public static void main(String[] args) {
List<Candidate> list = new ArrayList<Candidate>();
list.add(new Candidate("1","1","機構一"));//機構id,考生id，機構名稱。
list.add(new Candidate("1","2","機構一"));
list.add(new Candidate("2","3","機構二"));
list.add(new Candidate("2","4","機構二"));

List<CandidateOrg> CandidateOrgList

= new ArrayList<CandidateOrg>();
for (Candidate can : list) {
CandidateOrg canExist = null;
boolean bFound = false;
for (CandidateOrg candidateOrg : CandidateOrgList) {
if (candidateOrg.getOrgId().equals(can.getOrgId())) {
canExist = candidateOrg;
canExist.getCandidateIdList().add(can.getCandidateId());
bFound = true;
break;
}
}
if (!bFound) {
canExist = new CandidateOrg();//如果沒有找到就建立一個
canExist.setOrgId(can.getOrgId());
canExist.setOrgName(can.getOrgName());
List<String> candidateIdList = new ArrayList<String>();
canExist.setCandidateIdList(candidateIdList);
canExist.getCandidateIdList().add(can.getCandidateId());
}
if (!bFound) {
CandidateOrgList.add(canExist);
}
}
}

}

實現專案中的一個應用：