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面向对象不理解啊，过来看看

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//一个学校类有id和name两个字段，和一个student集合，都有自己的getter和setter
public class School {
int id;
String name;
List<Student> stus=new ArrayList<Student>();
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Student> getStus() {
return stus;
}
public void setStus(List<Student> stus) {
this.stus = stus;
}
}
1楼2014-10-18 22:44回复
    //一个student类有id、name、和所对应的school对象，有getter和setter
    public class Student {
    int id;
    String name;
    School school;
    public int getId() {
    return id;
    }
    public void setId(int id) {
    this.id = id;
    }
    public String getName() {
    return name;
    }
    public void setName(String name) {
    this.name = name;
    }
    public School getSchool() {
    return school;
    }
    public void setSchool(School school) {
    this.school = school;
    }
    }
    2楼2014-10-18 22:46
    回复
      //问题来了，我现在通过得到School对象，在通过school对象获取student，然后遍历student集合，
      //再往student.setSchool（）；这样可以吗？
      //假如school里有student对象
      public class UserMain {
      @Test
      public void test(){
      School sc=new School();
      List<Student> stus = sc.getStus();
      for(int i=0;i<stus.size();i++){
      stus.get(i).setSchool(sc);
      }
      }
      }
      3楼2014-10-18 22:51
      回复
        //这个事什么异常，难道是传说中的栈溢出
        java.lang.StackOverflowError
        at java.lang.ThreadLocal.get(ThreadLocal.java:143)
        at sun.misc.FloatingDecimal.developLongDigits(FloatingDecimal.java:329)
        at sun.misc.FloatingDecimal.dtoa(FloatingDecimal.java:566)
        at sun.misc.FloatingDecimal.<init>(FloatingDecimal.java:519)
        at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:657)
        at java.lang.StringBuilder.append(StringBuilder.java:229)
        at com.xiujie.domain.Employee.toString(Employee.java:46)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at java.util.AbstractCollection.toString(AbstractCollection.java:458)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Department.toString(Department.java:39)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        at com.xiujie.domain.Employee.toString(Employee.java:47)
        at java.lang.String.valueOf(String.java:2854)
        at java.lang.StringBuilder.append(StringBuilder.java:128)
        4楼2014-10-18 22:56
        回复
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at java.util.AbstractCollection.toString(AbstractCollection.java:458)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Department.toString(Department.java:39)
          at java.lang.String.valueOf(String.java:2854)
          at java.lang.StringBuilder.append(StringBuilder.java:128)
          at com.xiujie.domain.Employee.toString(Employee.java:47)
          at java.lang.String.valueOf(String.java:2854)
          5楼2014-10-18 22:58
          回复
            school可以.出student对吧，然后student又可以.出school对吧，举个简单粗暴的例子说，就是一只母猪生了一个小猪仔，这个猪仔又可以生母猪……不知道我这样理解能行不，面向对象我也是菜……
            IP属地:山东来自手机贴吧7楼2014-10-19 14:52
            回复
              Student里不要弄School了
              IP属地:北京来自Android客户端8楼2014-10-19 15:45
              回复

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