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一张图：一个类：Collections。三个知识点：foreach、generic(泛型)、Auto-boxing\unboxing(自动拆装箱)
六个接口：Collection、Set、List、Map、Iterator、Comparable
学习代码：
package com.pb.jbit.Collection;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
//定义一个雇员类
public class Employee {// javaBean实体类
private int id;
private String name;
private double salary;
private String department;
private Date date;
public Employee(int id, String name, double salary, String department,
String date) {
super();
this.id = id;
this.name = name;
this.salary = salary;
this.department = department;
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM");
try {
this.date = format.parse(date);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
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 double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
public String getDepartment() {
return department;
}
public void setDepartment(String department) {
this.department = department;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
}
测试一：利用对象来储存数据
package com.pb.jbit.Collection;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* 一个对象对应一条记录
* @author 李国梁
*
*/
public class test01 {
public static void main(String[] args) {
Employee e = new Employee(1001, "高淇", 3000, "项目部", "2007-09");
Employee e1 = new Employee(1001, "马士兵", 3000, "教学部", "2006-07");
Employee e2 = new Employee(1001, "斐新", 3000, "开发部", "2008-03");
List<Employee> list = new ArrayList<Employee>();
list.add(e);
list.add(e1);
list.add(e2);
// 方法一：
Iterator<Employee> iterator = list.iterator();
while (iterator.hasNext()) {
Employee employee = (Employee) iterator.next();
System.out.println(employee.getName() + "---" + employee.getDate());
}
System.out.println();
// 方法二：
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i).getName() + "---"
+ list.get(i).getDate());
}
System.out.println();
// 方法三：
for (Employee employee : list) {
System.out.println(employee.getName() + "---" + employee.getDate());
}
}
}
测试二：利用Map集合来储存数据
package com.pb.jbit.Collection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* 利用Map容器封装数据， 一个Map对应一条记录
*
* @author 李国梁
*
*/
public class test02 {
public static void main(String[] args) {
Map<Object, Object> map = new HashMap<Object, Object>();
map.put("id", 1001);
map.put("name", "高淇");
map.put("salary", 3500);
map.put("department", "项目部");
map.put("date", "2007-09");
Map<Object, Object> map1 = new HashMap<Object, Object>();
map1.put("id", 1002);
map1.put("name", "马士兵");
map1.put("salary", 3550);
map1.put("department", "教学部");
map1.put("date", "2006-09");
Map<Object, Object> map2 = new HashMap<Object, Object>();
map2.put("id", 1003);
map2.put("name", "斐新");
map2.put("salary", 3555);
map2.put("department", "开发部");
map2.put("date", "2003-09");
List<Map<Object, Object>> list = new ArrayList<Map<Object, Object>>();
list.add(map);
list.add(map1);
list.add(map2);
showslef(list);
}
public static void showslef(List<Map<Object, Object>> list) {
// 方法一：
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i).get("name") + "---"
+ list.get(i).get("date"));
}
System.out.println();
// 方法二：
for (Map<Object, Object> map : list) {
System.out.print(map.get("name"));
System.out.print("---");
System.out.println(map.get("date"));
}
System.out.println();
// 方法三：
Iterator<Map<Object, Object>> iterator = list.iterator();
while (iterator.hasNext()) {
Map<java.lang.Object, java.lang.Object> map = (Map<java.lang.Object, java.lang.Object>) iterator
.next();
System.out.print(map.get("name"));
System.out.print("---");
System.out.println(map.get("date"));
}
System.out.println();
// 方法四：
for (Iterator<Map<Object, Object>> iterator1 = list.iterator(); iterator1
.hasNext();) {
Map<java.lang.Object, java.lang.Object> map = (Map<java.lang.Object, java.lang.Object>) iterator1
.next();
System.out.print(map.get("name"));
System.out.print("---");
System.out.println(map.get("date"));
}
}
}
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