Java编程通过list接口实现数据的增删改查代码示例

package imooc; 
//课程类 
public class Course { 
  public String id; 
  public String name; 
  public Course(String id,String name){ 
    this.id=id; 
    this.name=name; 
  } 
  public Course(){} 
} 

package imooc; 
import java.util.ArrayList; 
import java.util.Arrays; 
import java.util.Iterator; 
import java.util.List; 
//备选课程类 
public class ListTest { 
  public List coursesToSelect; //定义一个List类，用于存放备选课程 
  public ListTest(){ 
    this.coursesToSelect=new ArrayList(); //ArraryList()方法 
  } 
  public void testAdd(){ 
    Course cr1=new Course("1","数据结构"); 
    coursesToSelect.add(cr1); //添加元素 
    Course temp=(Course)coursesToSelect.get(0); //取元素 
    System.out.println("添加了课程："+temp.id+":"+temp.name); 
    Course cr2=new Course("2","c语言"); 
    coursesToSelect.add(0, cr2); 
    Course temp2=(Course)coursesToSelect.get(0); 
    System.out.println("添加了课程："+temp2.id+":"+temp2.name); 
    //另一种添加方法 
    Course[] course={new Course("3","离散数学"),new Course("4","汇编语言")}; 
    coursesToSelect.addAll(Arrays.asList(course)); 
    Course temp3=(Course)coursesToSelect.get(2); 
    Course temp4=(Course)coursesToSelect.get(3); 
    System.out.println("添加了两门课程:"+ temp3.id+" "+temp3.name+" "+temp4.id+" "+temp4.name); 
    //另一种添加方法 
    Course[] course2={new Course("5","数字电路"),new Course("6","大学英语")}; 
    coursesToSelect.addAll(2, Arrays.asList(course2)); 
    Course temp5=(Course)coursesToSelect.get(2); 
    Course temp6=(Course)coursesToSelect.get(3); 
    System.out.println("添加了两门课程:"+ temp5.id+" "+temp5.name+" "+temp6.id+" "+temp6.name); 
  } 
  //遍历取得List中国的元素 
  public void testGet(){ 
    int size=coursesToSelect.size(); 
    System.out.println("有以下课程："); 
    for(int i=0;i