/** * 使用增强的for循环 * 在循环过程中从List中删除元素以后，继续循环List时会报ConcurrentModificationException */ public void listRemove() {
List<Student> students = this.getStudents();
for (Student stu : students) {
if (stu.getId() == 2) students.remove(stu);
}
}

/** * 像这种使用增强的for循环对List进行遍历删除，但删除之后马上就跳出的也不会出现异常 */ public void listRemoveBreak() {
List<Student> students = this.getStudents();
for (Student stu : students) {
if (stu.getId() == 2) {
students.remove(stu);
break;
}
}
}

/** * 这种遍历有可能会遗漏某个元素,因为删除元素后List的size在 * 变化，元素的索引也在变化，比如你循环到第2个元素的时候你把它删了， * 接下来你去访问第3个元素，实际上访问到的是原先的第4个元素。当访问的元素 * 索引超过了当前的List的size后还会出现数组越界的异常，当然这里不会出现这种异常， * 因为这里每遍历一次都重新拿了一次当前List的size。 */ public void listRemove2() {
List<Student> students = this.getStudents();
for (int i=0;
i<students.size();
i++) {
if (students.get(i).getId()%3 == 0) {
Student student = students.get(i);
students.remove(student);
}
}
}

/** * 使用Iterator的方式也可以顺利删除和遍历 */ public void iteratorRemove() {
List<Student> students = this.getStudents();
System.out.println(students);
Iterator<Student> stuIter = students.iterator();
while (stuIter.hasNext()) {
Student student = stuIter.next();
if (student.getId() % 2 == 0)//这里要使用Iterator的remove方法移除当前对象，如果使用List的remove方法，则同样会出现ConcurrentModificationException stuIter.remove();
}
System.out.println(students);
}

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class ListRemove {
public static void main(String args[]) {
ListRemove lr = new ListRemove();
lr.listRemove();
lr.listRemoveBreak();
// lr.listRemove2();
// lr.iteratorRemove();
}
/** * 使用增强的for循环 * 在循环过程中从List中删除元素以后，继续循环List时会报ConcurrentModificationException */ public void listRemove() {
List<Student> students = this.getStudents();
for (Student stu : students) {
if (stu.getId() == 2) students.remove(stu);
}
}
/** * 像这种使用增强的for循环对List进行遍历删除，但删除之后马上就跳出的也不会出现异常 */ public void listRemoveBreak() {
List<Student> students = this.getStudents();
for (Student stu : students) {
if (stu.getId() == 2) {
students.remove(stu);
break;
}
}
}
/** * 这种不使用增强的for循环，每次重新获取list的size遍历的情况运行时不会报错，但是可能删除的结果是错的。 */ public void listRemove2() {
List<Student> students = this.getStudents();
for (int i=0;
i<students.size();
i++) {
if (students.get(i).getId()%2 == 0) students.remove(i);
}
}
/** * 使用Iterator的方式也可以顺利删除和遍历 */ public void iteratorRemove() {
List<Student> students = this.getStudents();
System.out.println(students);
Iterator<Student> stuIter = students.iterator();
while (stuIter.hasNext()) {
Student student = stuIter.next();
if (student.getId() % 2 == 0) stuIter.remove();
}
System.out.println(students);
}
private List<Student> getStudents() {
List<Student> students = new ArrayList<Student>() {
{
int i = 0;
while (i++ < 10) {
Student student = new Student(i, "201200" + i, "name_" + i);
this.add(student);
}
}
}
;
return students;
}
}

public class Student {
private int id;
private String stuNo;
private String name;
public Student() {
}
public Student(int id, String stuNo, String name) {
this.id = id;
this.stuNo = stuNo;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getStuNo() {
return stuNo;
}
public void setStuNo(String stuNo) {
this.stuNo = stuNo;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override public String toString() {
return "Student [id=" + id + ", name=" + name + ", stuNo=" + stuNo + "]";
}
}