数据库CRUD增删改查操作模拟

数据库CRUD增删改查操作模拟：

0.首先先创建啊一个Person类，录入属性string name，int age

1-创建IBaseService接口，用到了范型<T,K>
2-创建与表关联的接口 例如 IPersonService,
3-创建实现类 class PersonService implements 
IPersonService{CRUD....--List--ArrayList}

4-实现PersonAction,调用PersonService的CRUD方法，实现测试功能

1-

package com.company.demo.list;//1import java.util.List;public interface IBaseService<T,K> {// 模糊查询public List<T> findByName(String name);// 根据id查询public T findById(K id);// Read Query 查询所有public List<T> findAll();// Create 增加 Savepublic String save(T t);// Update 修改public String update(T newt);// Delete 删除public String delete(T t);}

2-

package com.company.demo.list;//2import com.company.demo.pojo.Person;public interface IPersonService extends IBaseService<Person,Integer> {}

3-

package com.company.demo.list;//3import java.util.ArrayList;import java.util.List;import com.company.demo.pojo.Person;/** *  * @author Administrator * save * update * delete * findAll * findById * findByName */public class PersonService implements IPersonService{public static List<Person> personDB;static {personDB = new ArrayList<Person>();}// 增删改查 CRUD操作//模糊查询public List<Person> findByName(String name){List<Person> persons = new ArrayList<Person>();for(Person p:personDB){if(p.getName().indexOf(name) != -1){persons.add(p);}}return persons.size()==0?null:persons;}// 根据id查询public Person findById(Integer id) {for (Person p : personDB) {if (id == p.getId()) {return p;}}return null;}// Read Query 查询所有public List<Person> findAll() {return personDB;}// Create 增加 Savepublic String save(Person person) {personDB.add(person);return "save success";}// Update 修改public String update(Person newPerson){Person p = findById(newPerson.getId());if(p!=null){p.setName(newPerson.getName());return "update success";}else{return "update error";}}// Delete 删除public String delete(Person person) {boolean flag = personDB.remove(person);return flag ? "delete success" : "delete error";}}

4-注释内容可以随意删改

package com.company.demo.list;import java.util.List;import com.company.demo.pojo.Person;//4public class PersonAction {public static void main(String[] args) {IPersonService ps = new PersonService();ps.save(new Person(1001,"zhao"));ps.save(new Person(1002,"qian"));Person sun = new Person(1003,"sun");ps.save(sun);ps.save(new Person(1004,"li"));//ps.delete(sun);//ps.update(new Person(1004,"ookk"));//System.out.println(ps.update(new Person(1094,"ookk")));//List<Person> persons = ps.findAll();//for(Person person:persons)//System.out.println(person);//Person person1 = ps.findById(1001);//Person person2 = ps.findById(1011);//System.out.println(person1);//System.out.println(person2);List<Person> persons = ps.findByName("a");for(Person person:persons){System.out.println(person);}}}