java基于对象流实现银行系统的具体代码，供大家参考，具体内容如下
系统特点：
- 数据持久化到文件中，系统启动后，加载文件中数据到集合中，相当于做了一个缓存。
- 文件读写使用的是对象流（objectinputstream和objectoutputstream），用户是看不懂那些文件的，一定程度上保证了密码和余额的安全性。
- 采用了mvc分层设计思想，虽然没有c控制层和v视图层，但是有完备的m模型层，数据处理service，数据读写dao，数据存储pojo（每一层只负责处理自己的事情，层次内部的改动不会影响其他层次）。
- 虽然有些细节问题由于时间关系没有处理好，比如没有处理输入类型不匹配的异常，但是绝大多数功能都合理得实现了。
全部代码
pojo：
public class user implements serializable {
private static final long serialversionuid = -7019656536540026883l;
private string username;//用户名
private string password;//密码
private double balance;//余额
public user(string username, string password, double balance) {
this.username = username;
this.password = password;
this.balance = balance;
}
public user() {
}
public string getusername() {
return username;
}
public void setusername(string username) {
this.username = username;
}
public string getpassword() {
return password;
}
public void setpassword(string password) {
this.password = password;
}
public double getbalance() {
return balance;
}
public void setbalance(double balance) {
this.balance = balance;
}
public string tostring(){
stringbuilder builder = new stringbuilder("{");
builder.append(this.username).append(",").append(this.password).append(",").append(this.balance).append("}");
return builder.tostring();
}
dao层：
public class atmdao {
private string userfilepath = "src\\usermsg.txt";//相对路径
private hashmap<string, user> usermsg;
{
usermsg = this.loadfile();//读取文件信息
}
public hashmap<string, user> getusermsg() {
return usermsg;
}
//查询用户
public user selectuser(string username){
return usermsg.get(username);
}
//更新用户信息
public void updateuser(user user){
this.usermsg.replace(user.getusername(),user);
this.updatefile(usermsg);
}
//增加用户
public void adduser(user user){
this.usermsg.put(user.getusername(),user);
this.updatefile(usermsg);
}
//删除用户
public void deleteuser(user user){
this.usermsg.remove(user.getusername());
this.updatefile(usermsg);
}
//只在初始化时时调用一次
/* public void initfile(){
user user1 = new user("张三","123",800.0);
user user2 = new user("李四","666",70.0);
user user3 = new user("王五","888",555.0);
usermsg.put(user1.getusername(),user1);
usermsg.put(user2.getusername(),user2);
usermsg.put(user3.getusername(),user3);
this.updatefile(usermsg);
}*/
private hashmap<string, user> loadfile(){
file file = new file(userfilepath);
fileinputstream fis = null;
objectinputstream ois = null;
hashmap<string, user> box = null;
try {
fis = new fileinputstream(file);
ois = new objectinputstream(fis);
try {
box = (hashmap<string, user>)ois.readobject();
} catch (classnotfoundexception e) {
e.printstacktrace();
}
} catch (ioexception e) {
e.printstacktrace();
}finally {
try {
if(fis!=null)
fis.close();
} catch (ioexception e) {
e.printstacktrace();
}
try {
if(ois!=null)
ois.close();
} catch (ioexception e) {
e.printstacktrace();
}
}
return box;
}
private void updatefile(hashmap<string,user> usermsg){
file file = new file(userfilepath);
fileoutputstream fos = null;
objectoutputstream oos = null;
try {
fos = new fileoutputstream(file);
oos = new objectoutputstream(fos);
oos.writeobject(usermsg);
oos.flush();
} catch (ioexception e) {
e.printstacktrace();
}finally {
try {
if(fos!=null)
fos.close();
} catch (ioexception e) {
e.printstacktrace();
}
try {
if(oos!=null)
oos.close();
} catch (ioexception e) {
e.printstacktrace();
}
}
}
}
service层：
public class atmservice {
atmdao dao = new atmdao();
public boolean login(string username,string password){
user user = dao.selectuser(username);
if (user!=null && user.getpassword().equals(password))
return true;
else
return false;
}
//查询余额
public double querybalance(string name){
user user = dao.selectuser(name);
return user.getbalance();
}
//存款
public void deposit(string name,double account){
user user = dao.selectuser(name);
user.setbalance(user.getbalance()+account);
dao.updateuser(user);
}
//取款
public void withdrawal(string name,double account){
user user = dao.selectuser(name);
if (user.getbalance()>=account) {
user.setbalance(user.getbalance() - account);
dao.updateuser(user);
}else {
system.err.println("对不起，"+user.getusername()+"，您的余额不足");
}
}
//转账
public void transfer(string oldname,string newname,double account){
user olduser = dao.selectuser(oldname);
user newuser = dao.selectuser(newname);
if (newuser!=null){
if (olduser.getbalance()>=account){
olduser.setbalance(olduser.getbalance()-account);
newuser.setbalance(newuser.getbalance()+account);
dao.updateuser(olduser);
dao.updateuser(newuser);
}else {
system.err.println("对不起，"+olduser.getusername()+"，您的余额不足");
}
}else {
system.err.println("对不起，您输入的账号不存在");
}
}
//销户
public void closeaccount(string name){
user u = dao.selectuser(name);
dao.deleteuser(u);
}
//注册
public void register(string name,string password){
user user = dao.selectuser(name);
if (user!=null){
system.err.println("对不起，您输入的账号已存在");
}else {
user = new user(name,password,0.0);
dao.adduser(user);
}
}
}
测试：
public class test {
public static void main(string[] args) {
atmservice service = new atmservice();
scanner input = new scanner(system.in);
system.out.println("欢迎您使用银行自助服务系统\n请输入您的账号:");
string username = input.nextline();
system.out.println("请输入您的密码：");
string password = input.nextline();
if (service.login(username,password)){
system.out.println("登录成功!");
while(true) {
system.out.println("请选择您的操作：\n0.注册\n1.查询余额\n2.存款\n3.取款\n4.转账\n5.销户\n6.退出");
string option = input.nextline();
switch (option) {
case "0":
system.out.println("请输入您的用户名：");
string newname = input.nextline();
system.out.println("请输入您的密码：");
string newpass = input.nextline();
service.register(newname, newpass);
system.out.println("恭喜您，注册成功！，您的用户名为" + newname);
break;
case "1":
double balance = service.querybalance(username);
system.out.println("您的余额为" + balance);
break;
case "2":
system.out.println("请输入存款金额：");
double amount = input.nextdouble();
input.nextline();
service.deposit(username, amount);
system.out.println("恭喜您，存款成功");
break;
case "3":
system.out.println("请输入取款金额：");
double d = input.nextdouble();
input.nextline();
service.withdrawal(username, d);
system.out.println("恭喜您，取款成功");
break;
case "4":
system.out.println("请输入对方账户：");
string anothername = input.nextline();
system.out.println("请输入转账金额：");
double t = input.nextdouble();
input.nextline();
service.transfer(username, anothername, t);
system.out.println("恭喜您，转账成功");
break;
case "5":
service.closeaccount(username);
system.out.println("销户成功");
break;
case "6":
system.exit(0);
}
}
}else {
system.err.println("用户名或密码错误");
}
//dao.initfile();
/*hashmap<string, user> usermsg = dao.getusermsg();
iterator<string> iterator = usermsg.keyset().iterator();
while (iterator.hasnext()){
string username = iterator.next();
user user = usermsg.get(username);
system.out.println(user);
}*/
}
}
部分测试截图
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。
