图书管理系统的部分操作（java）

1、user.java文件
定义用户

定义时，写出变量，private int id;

private String name;

private String pwd;

private String email;

然后右击

选择Source，

选择Generate Getters and Setters...,select all

选择Generate hash() and equals()...,选择id

选择Generate Constructor using Fields...

选择Generate Constructor from Superclass...

public class User {

private int
id;

private
String name;

private
String pwd;

private
String email;

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
String getPwd() {

return
pwd;

}

public void
setPwd(String pwd) {

this.pwd =
pwd;

}

public
String getEmail() {

return
email;

}

public void
setEmail(String email) {

this.email =
email;

}

public
User() {

}

public User(
int id, String name, String pwd,String email)
{

super();

this.email =
email;

this.id =
id;

this.name =
name;

this.pwd =
pwd;

}

@Override

public int
hashCode()
{
添加hash（）和equals（）方法（以id为基准）

final int
prime = 31;

int result =
1;

result =
prime * result + id;

return
result;

}

@Override

public
boolean equals(Object obj) {

if (this ==
obj)

return
true;

if (obj ==
null)

return
false;

if
(getClass() != obj.getClass())

return
false;

User other =
(User) obj;

if (id !=
other.id)

return
false;

return
true;

}

//toString
软件少用!!! 显示字符串

public
String
toString(){

return
this.id+this.name+this.pwd+this.email;

}

}

2、方法总

public interface IUserManager {

void
reg(String name, String pwd, String email);// 注册

User
login(String name, String pwd);// 登录

void
updatePwd(int id, String pwd);// 更新口令

User[]
findAll();// 查询所有用户

User
findById(int id);// 依据id查找用户

User
findByName(String name); // 依据名字查找用户

User
findByEmail(String email); // 依据邮件查询用户

}

3、方法的填写

import java.util.Collection;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;

import java.util.Scanner;

import java.util.List;

import java.util.ArrayList;

import
java.util.Set;
跟据需要引包

public class UserMangerImpl implements
IUserManager {

private
static int count = 1;

public
static Map<String, User> db = new
HashMap<String, User>();

//
@Override

// public
User[] findAll() {

//

Collection<User> all =
db.values();

//
return
all.toArray(new User[0]); // 转换成数组类型

//

// }

@Override

public User
findByEmail(String email)
{
// 依据邮件查询用户

Collection<User> c1 =
db.values();

Iterator<User> it =
c1.iterator();

while
(it.hasNext()) {

User u =
it.next();

if
(u.getEmail().equals(email) )

return
u;

}

return
null;

}

@Override

public User
findById(int id)
{
// 依据id查询用户

Collection<User> c1 =
db.values();

for (User u
: c1) {

if
(u.getId() == id) {

return
u;

}

}

return
null;

}

@Override

public User
findByName(String name)
{
// 依据用户名查询用户

return
db.get(name);

}

@Override

public User
login(String name, String pwd)
{
//登陆

User u =
db.get(name);

if (u ==
null) {

System.out.println("wrong");

}

if
(!u.getPwd().equals(pwd)) {

System.out.println("the passwords are wrong");

}

return
u;

}

@Override

public void
reg(String name, String pwd, String email) {
//注册

if (true ==
db.containsKey(name)) {

throw new
IllegalArgumentException("用户已存在");

}

User u = new
User(count++, name, pwd, email);

db.put(name,
u);

}

@Override

public void
updatePwd(int id, String pwd)
{
//更新

User u =
findById(id);

if (u ==
null) {

System.out.println("指定的用户不存在");

}

u.setPwd(pwd);

}

@Override

public
User[] findAll() {

// TODO
Auto-generated method stub

return
null;

}

}

4、方法的测试

import java.util.Collection;

import java.util.Iterator;

import java.util.Scanner;

public class test {

public
static void main(String[] args) {

IUserManager
um = new UserMangerImpl();

um.reg("aaa", "111", "emali@1");

um.reg("bbb", "222", "emali@2");

um.reg("ccc", "333", "emali@3");

um.updatePwd(1, "456");

System.out.println(um.login("aaa", "111"));

System.out.println(um.login("bbb", "222"));

System.out.println(um.login("ccc", "333"));

System.out.println(um.findById(1));

System.out.println(um.findById(2));

System.out.println(um.findById(4));

System.out.println(um.findByName("aaa"));

System.out.println(um.findByName("bb3"));

System.out.println(um.findByName("cc3"));

System.out.println(um.findByEmail("emali@6"));

System.out.println(um.findByEmail("emali@2"));

System.out.println(um.findByEmail("emali@3"));

User a[] =
um.findAll();

for (int i =
0; i < a.length; i++)

System.out.println(a[i]);

Collection<User> c1 =
UserMangerImpl.db.values();

Iterator<User> it =
c1.iterator();

while
(it.hasNext()) {

User u =
it.next();

System.out.println(u);

}

}

}

5、

import java.util.Scanner;

public class Ul {

static
IUserManager manager = new UserMangerImpl();

static
boolean stop = true;

public
static void main(String[] args) {

System.out.println("根据提示输入信息");

Scanner sc =
new Scanner(System.in);

while (stop)
{

System.out.println

("1注册,2登陆，3显示用户信息，4用用户名查找某个用户，5用邮箱查找某个用户，6更改密码");

String cmd =
sc.nextLine();

if
("1".equals(cmd)) {

System.out.println("输入姓名");

String name
= sc.nextLine();

System.out.println("输入密码");

String pwd =
sc.nextLine();

System.out.println("输入邮箱");

String email
= sc.nextLine();

manager.reg(name, pwd, email);

}

if
("3".equals(cmd)) {

User[] c1 =
manager.findAll();

for (User u
: c1)

System.out.println(u);

}

if
("2".equals(cmd)) {

System.out.println("输入姓名");

String name
= sc.nextLine();

if (name ==
null) {

System.out.println("wrong");

}

System.out.println("输入密码");

String pwd =
sc.nextLine();

System.out.println(manager.login(name, pwd));

}

if
("4".equals(cmd)) {

System.out.println("输入姓名");

String name
= sc.nextLine();

if (name ==
null) {

System.out.println("wrong");

}

System.out.println(manager.findByName(name));

}

if
("5".equals(cmd)) {

System.out.println("输入邮箱");

String email
= sc.nextLine();

if (email ==
null) {

System.out.println("wrong");

}

System.out.println(manager.findByEmail(email));

}

if
("6".equals(cmd)) {

System.out.println("输入要更改密码的用户名");

String name
= sc.nextLine();

if (name ==
null) {

System.out.println("wrong");

}

manager.updatePwd(1, "456");

}

}

}

}