表格存储数据

map和list结合存储整张表

每行数据使用一个：Map

整个表格使用一个List

ORM思想：对象关系映射

    package cn.yishan.collection;

    import java.util.*;

    /**
    * 测试表格数据的存储
    * @author yishan
    */
    public class TestStoreData {
        public static void main(String[] args) {

            Map<String, Object> row1 = new HashMap<>();
            row1.put("id",1001);
            row1.put("姓名","张三");
            row1.put("薪水","2000");
            row1.put("入职日期","2001.5.2");

            Map<String, Object> row2 = new HashMap<>();
            row2.put("id",1002);
            row2.put("姓名","李四");
            row2.put("薪水","3000");
            row2.put("入职日期","2010.4.8");

            Map<String, Object> row3 = new HashMap<>();
            row3.put("id",1003);
            row3.put("姓名","王五");
            row3.put("薪水","4500");
            row3.put("入职日期","2010.7.9");

            List<Map<String, Object>> table1 = new ArrayList<>();
            table1.add(row1);
            table1.add(row2);
            table1.add(row3);

            for (Map<String, Object> row:table1){
                Set<String> keyset = row.keySet();

                for (String key:keyset){
                    System.out.print(key+":"+row.get(key)+"\t");
                }
                System.out.println();
            }
        }
    }

javabean和list结合存储整张表

每一行数据使用一个：javabean对象

整个表格使用一个：Map/List

    package cn.yishan.collection;

    import java.util.*;

    /**
    * 测试表格数据的存储
    * 体会ORM思想
    * 每一行数据使用javabean对象存储，多行使用放到map或者list中
    * @author yishan
    */
    public class TestStoreData2 {
        public static void main(String[] args) {
            User user1 = new User(1001,"张三",2000,"2001.5.6");
            User user2 = new User(1002,"李四",3000,"2002.6.8");
            User user3 = new User(1003,"王五",4000,"2006.9.6");

            List<User> list = new ArrayList<>();
            list.add(user1);
            list.add(user2);
            list.add(user3);

            for (User u:list){
                System.out.println(u);
            }
            System.out.println("--------------------------------------------");
            Map<Integer, User> map = new HashMap<>();
            map.put(1001,user1);
            map.put(1002,user2);
            map.put(1003,user3);
            Set<Integer> keyset = map.keySet();
            for (Integer key:keyset){
                System.out.println(key+"--"+map.get(key));
            }
        }
    }

    class User{
        private int id;
        private String name;
        private double salary;
        private String hiredate;

        //一个完整的javabean。要有set和get方法，以及无参的构造器
        public User(){}
        public User(int id, String name, double salary, String hiredate) {
            this.id = id;
            this.name = name;
            this.salary = salary;
            this.hiredate = hiredate;
        }

        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 getHiredate() {
            return hiredate;
        }

        public void setHiredate(String hiredate) {
            this.hiredate = hiredate;
        }

        @Override
        public String toString() {
            return "id:"+id+",name:"+name+",salary:"+salary+",hiredate:"+hiredate;
        }
    }

赏

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