java常用类练习05（用户注册、查询、修改、删除）

package com.oracle.user;

import java.util.ArrayList;
import java.util.Scanner;

/**
* 用户注册
* @author user
*
*/
public class Reg {

static Scanner sc = new Scanner(System.in);static ArrayList<User> list = new ArrayList<User>();/** * 注册功能的方法 * @param args */public static User zhuce(){    User u = new User();    System.out.println("请输入姓名：");    String name =  sc.next();    u.setName(name);    System.out.println("请输入密码：");    String pwd = sc.next();    u.setPwd(pwd);    return u;}/** * 查询集合中的用户 * @param args */public static void findUser(){    for (User user : list) {        System.out.println(user);    }}/** * 修改用户的方法 * @param args */public static void updateUser(){    System.out.println("请输入要修改的用户名：");    String name = sc.next();    User u = null;    for (User user : list) {        if(user.getName().equals(name)){            u = user;        }    }    if(u == null){        System.out.println("查无此人");        return;    }    int index = list.indexOf(u);    System.out.println("请输入修改后的姓名：");    String name2 = sc.next();    System.out.println("请输入修改后的密码：");    String pwd = sc.next();    list.set(index, new User(name2,pwd));    System.out.println("修改成功");}/** * 删除用户 * @param args */public static void del(){    System.out.println("请输入要删除的用户名：");    String name = sc.next();    User u = null;    for (User user : list) {        if(user.getName().equals(name)){            u = user;        }    }    if(u == null){        System.out.println("查无此人");        return;    }

// int index = list.indexOf(u);
// list.remove(index);

    boolean b = list.remove(u);    if(b){        System.out.println("删除成功");    }else{        System.out.println("删除失败");    }}public static void main(String[] args) {    System.out.println("============用户注册============");    a: while(true){        System.out.println("请选择：1.注册用户；2.查看用户；3.修改用户；4.删除用户；0.退出");        int i = sc.nextInt();        switch(i){        case 1:            User u = zhuce();            list.add(u);            break;        case 2:            if(list.size()<=0){                System.out.println("当前没有用户数据，请先注册！");            }else{                findUser();            }            break;        case 3:            updateUser();            break;        case 4:            del();            break;        case 0:            break a;        }    }    System.out.println("============再见============");}

}

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package com.oracle.user;

public class User {

private String name;private String pwd;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 User() {    super();    // TODO Auto-generated constructor stub}public User(String name, String pwd) {    super();    this.name = name;    this.pwd = pwd;}@Overridepublic String toString() {    return "User [name=" + name + ", pwd=" + pwd + "]";}   

}

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package com.oracle.user;

import java.util.ArrayList;

public class Test {

public static void main(String[] args) {    ArrayList<User> list = new ArrayList<User>();    //添加    User u1 = new User("tom","123");    User u2 = new User("jack","456");    list.add(u1);    list.add(u2);    User u = null;    for (User user : list) {        if(user.getName().equals("tom")){            u = user;//把从集合中遍历到的符合姓名的对象地址，赋给u对象        }    }    int i = list.indexOf(u);    System.out.println(i);

// System.out.println(list);

    //查看集合的长度

// System.out.println(“长度=”+list.size());

    //修改

// list.set(0, );

// System.out.println(list);

    //删除

// boolean b = list.remove(u);
// System.out.println(b);

// User user = list.remove(0);
// System.out.println(user.getName()+”被删除了”);
// System.out.println(“删除后的长度=”+list.size());
}
}