java day42【综合练习】

第一章   综合练习

1. 简单功能
1. 列表查询
2. 登录
3. 添加

 

4. 删除

 

5. 修改

 

2. 复杂功能
1. 删除选中

 

2. 分页查询

* 好处：
1. 减轻服务器内存的开销
2. 提升用户体验
3. 复杂条件查询

第二章  登录

1. 调整页面，加入验证码功能
2. 代码实现

代码实现：

UserDao.java

package cn.itcast.dao;

import cn.itcast.domain.User;

import java.util.List;
import java.util.Map;

/**
* 用户操作的DAO
*/
public interface UserDao {

public List findAll();

User findUserByUsernameAndPassword(String username, String password);

void add(User user);

void delete(int id);

User findById(int i);

void update(User user);

/**
* 查询总记录数
* @return
* @param condition
*/
int findTotalCount(Map condition);

/**
* 分页查询每页记录
* @param start
* @param rows
* @param condition
* @return
*/
List findByPage(int start, int rows, Map condition);
}

UserDaoImpl(1).java

package cn.itcast.dao.impl;

import cn.itcast.dao.UserDao;
import cn.itcast.domain.User;
import cn.itcast.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class UserDaoImpl implements UserDao {

private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

@Override
public List findAll() {
//使用JDBC操作数据库...
//1.定义sql
String sql = "select * from user";
List users = template.query(sql, new BeanPropertyRowMapper(User.class));

return users;
}

@Override
public User findUserByUsernameAndPassword(String username, String password) {
try {
String sql = "select * from user where username = ? and password = ?";
User user = template.queryForObject(sql, new BeanPropertyRowMapper(User.class), username, password);
return user;
} catch (Exception e) {
e.printStackTrace();
return null;
}

}

@Override
public void add(User user) {
//1.定义sql
String sql = "insert into user values(null,?,?,?,?,?,?,null,null)";
//2.执行sql
template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail());
}

@Override
public void delete(int id) {
//1.定义sql
String sql = "delete from user where id = ?";
//2.执行sql
template.update(sql, id);
}

@Override
public User findById(int id) {
String sql = "select * from user where id = ?";
return template.queryForObject(sql, new BeanPropertyRowMapper(User.class), id);
}

@Override
public void update(User user) {
String sql = "update user set name = ?,gender = ? ,age = ? , address = ? , qq = ?, email = ? where id = ?";
template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
}

@Override
public int findTotalCount(Map condition) {
//1.定义模板初始化sql
String sql = "select count(*) from user where 1 = 1 ";
StringBuilder sb = new StringBuilder(sql);
//2.遍历map
Set keySet = condition.keySet();
//定义参数的集合
List