JAVAList求和问题

我现在有三个List List里的对象是两个bean，我想要的条件是：list1和list2比较如果对象主键相等，累加添加到list3中。最后如果list1里的数据没有在list2中的数据，添加到list3中。如果list2没有在list1中，添加到list3中。
例：
bean1：
[code="java"]
public class Hyflightmanifest{
private String flightnumber;

  private String inflag;

  private Date schdate;

  pirvate int num;
public String getFlightnumber() {
    return flightnumber;
}

public void setFlightnumber(String flightnumber) {
    this.flightnumber = flightnumber;
}

public String getInflag() {
    return inflag;
}

public void setInflag(String inflag) {
    this.inflag = inflag;
}

public Date getSchdate() {
    return schdate;
}

public void setSchdate(Date schdate) {
    this.schdate = schdate;
}

public int getNum() {
    return num;
}

public void setNum(int num) {
    this.num= num;
}

}
[/code]
bean2：
[code="java"]
public class manifestbean{
private String flightnumber;

  private String inflag;

  private Date schdate;

  pirvate int num;

public String getFlightnumber() {
    return flightnumber;
}

public void setFlightnumber(String flightnumber) {
    this.flightnumber = flightnumber;
}

public String getInflag() {
    return inflag;
}

public void setInflag(String inflag) {
    this.inflag = inflag;
}

public Date getSchdate() {
    return schdate;
}

public void setSchdate(Date schdate) {
    this.schdate = schdate;
}

public int getNum() {
    return num;
}

public void setNum(int num) {
    this.num= num;
}

}
[/code]

[code="java"]
List maillist = cosysfightservicemailService.getBySeletive(example);

        for (int i = 0; i < flightmanifestTempList.size(); i++) {
            Hyflightmanifest manifestbean = new Hyflightmanifest();
            manifestbean = flightmanifestTempList.get(i);
            Date tempSchdate = manifestbean.getSchdate();
            manifestbean.setSchdate(Tools.getDateByStr("yyyy-MM-dd", Tools.getStrByDate("yyyy-MM-dd", tempSchdate)));
            for (int j = 0; j < maillist.size(); j++) {
                Hycosysfightservicemail mailbean = new Hycosysfightservicemail();
                if ((mailbean.getFlightnumber().trim()).equals(manifestbean.getFlightnumber().trim()) && (mailbean.getInflag().trim()).equals(manifestbean.getInflag().trim())
                        && (mailbean.getActualdate().getTime() == manifestbean.getSchdate().getTime())) {

                }
            }
        }

[/code]
[b]请问大家接着怎么做[/b]

基本思路如下(只能是1:1或者1:0匹配)
遍历list1，从list2查找匹配的，并且把找到删除
如果没有匹配的，直接加入list3

最后把list2剩下的加入list3

//List list1, list2;
List list3= new ArrayList();

// 实现查找，没有则返回null
manifestbean findAndRemoveFromList2(Hyflightmanifest f) {
for (Iterator it= list2.iterator(); it.hasNext()) {
manifestbean m= (manifestbean) it.next();
if PK相等 {
it.remove();
return m;
}
}
// no found
return null;
}
public void merge() {
for (Iterator it= list.iterator(); it.hasNext()) {
Hyflightmanifest h= (Hyflightmanifest) it.next();
m= findAndRemoveFromList2(h);
// 有则相加
if (null != m) {
}
// 无则直接加入list3
list3.add(h);
}
// 把list2剩下的加入list3
for (Iterator it= list2.iterator(); it.hasNext()) {

}
}