JSP中的DAO是干什么的?如何来使用 请举例说明 请注释 谢谢 !!!
解决方案 »
- 求救:关于网上付费的一个项目,银行给了接口 可不知道怎么连接!
- HttpURLConnection中用StringBuffer获取内容时,会OutOfMemory
- jsp怎么接收并判断 Action设置在request里的变量和值
- 用spring 发送邮件,已经设置了主题(subject),收到的邮件中没有主题,怎么样解决?
- Struct工程运行时报 java.lang.NoClassDefFoundError: org/apache/commons/beanutils/Converter 请问如何解决
- 大家好,请教一个问题,很久了一直没办法解决啊!
- 在structs中,链接中的参数传递问题!
- 计论开源工作流项目, OsWorkFlow
- 除了做网页,JAVA到底有什么用。困惑呀。帮忙解惑吧
- 我用的是TOMCAT5.0,servlet编译生成的字节码文件要放在哪个目录下才能正常运行?
- ServletContext 为NULL的问题,谢谢帮忙,等
- 求将mysql数据导出成excel文件的方法
package com.dwp.dao;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.List;import com.dwp.daos.ListDao;
import com.dwp.daos.ListDaoImpl;
import com.dwp.pojo.User;
import com.dwp.util.DataSource;public class UserDaoImpl implements UserDao {
//保存
/* (non-Javadoc)
* @see com.dwp.dao.UserDao#save(com.dwp.pojo.User)
*/
public boolean save(User user) {
boolean flag = false;
//创建数据库
DataSource ds = new DataSource();
Connection conn = ds.getConnection();
//创建stmt
PreparedStatement stmt = null;
try {
//设置事务的提交方式为手动
conn.setAutoCommit(false);
stmt = conn.prepareStatement("insert into Users(loginName,userName,gender,birthday,password) values(?,?,?,?,?)");
stmt.setString(1, user.getLoginName());
stmt.setString(2, user.getUserName());
stmt.setString(3, user.getGender());
//把java.util.Date转换为java.sql.Date 如果带有时间java.sql.Timestamp
stmt.setDate(4, new java.sql.Date(user.getBirthday().getTime()));
stmt.setString(5, user.getPassword());
//执行sql语句
stmt.executeUpdate();
//提交事务
conn.commit();
flag = true;
} catch (SQLException e) {
e.printStackTrace();
try {
//事务回滚
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
} finally {
ds.close(conn, stmt);
}
return flag;
}
//删除
/* (non-Javadoc)
* @see com.dwp.dao.UserDao#delete(com.dwp.pojo.User)
*/
public boolean delete(User user) {
return delete(user.getId());
}
/* (non-Javadoc)
* @see com.dwp.dao.UserDao#delete(int)
*/
public boolean delete(int id) {
boolean flag = false;
//创建数据库
DataSource ds = new DataSource();
Connection conn = ds.getConnection();
//创建stmt
PreparedStatement stmt = null;
try {
//设置事务的提交方式为手动
conn.setAutoCommit(false);
stmt = conn.prepareStatement("delete from Users where id=?");
stmt.setInt(1, id);
//执行sql语句
stmt.executeUpdate();
//提交事务
conn.commit();
flag = true;
} catch (SQLException e) {
e.printStackTrace();
try {
//事务回滚
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
} finally {
ds.close(conn, stmt);
}
return flag;
}
//修改
/* (non-Javadoc)
* @see com.dwp.dao.UserDao#update(com.dwp.pojo.User)
*/
public boolean update(User user) {
boolean flag = false;
//创建数据库
DataSource ds = new DataSource();
Connection conn = ds.getConnection();
//创建stmt
PreparedStatement stmt = null;
try {
//设置事务的提交方式为手动
conn.setAutoCommit(false);
stmt = conn.prepareStatement("update Users set loginName=?,userName=?,gender=?,birthday=?,password=? where id=?");
stmt.setString(1, user.getLoginName());
stmt.setString(2, user.getUserName());
stmt.setString(3, user.getGender());
//把java.util.Date转换为java.sql.Date 如果带有时间java.sql.Timestamp
stmt.setDate(4, new java.sql.Date(user.getBirthday().getTime()));
stmt.setString(5, user.getPassword());
stmt.setInt(6, user.getId());
//执行sql语句
stmt.executeUpdate();
//提交事务
conn.commit();
flag = true;
} catch (SQLException e) {
e.printStackTrace();
try {
//事务回滚
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
} finally {
ds.close(conn, stmt);
}
return flag;
}
//查询
/* (non-Javadoc)
* @see com.dwp.dao.UserDao#getUserById(int)
*/
public User getUserById(int id) {
User user = null;
ListDao listDao = new ListDaoImpl();
List<User> userList = listDao.getList(User.class,
"select * from Users where id=?", new Object[]{id});
for(User tempUser : userList) {
user = tempUser;
}
return user;
}
/**
* 显示所有的Users记录
*/
public List<User> getUserMessage() {
ListDao listDao = new ListDaoImpl();
List<User> userList = listDao.getList(User.class,
"select * from Users");
return userList;
}
}