一个基于struts的对用户进行增删查改的代码续

dao包代码:
import java.sql.Connection;
import java.util.List;

import com.bjsxt.drp.business.usermgr.model.User;

/**
* 用户增删改查Dao层接口
*/
public interface UserDao {

/**
* 增加用户
* @param conn
* @param user user对象 
*/
public void addUser(Connection conn, User user);

/**
* 根据userId的集合删除用户
* @param conn
* @param userIdList  userId的集合
*/
public void deleteUsers(Connection conn, String[] userIdList);

/**
* 修改用户
* @param conn
* @param user user对象 
*/
public void modifyUser(Connection conn, User user);

/**
* 根据用户id查询用户
* @param userId 用户id
* @return  user对象 
*/
public User findUserById(String userId);

/**
* 查询所有用户
* @return user对象列表
*/
public List findAllUserList();
}

dao实现

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;

import com.bjsxt.drp.business.usermgr.model.User;
import com.bjsxt.drp.business.util.DB;

/**
* 用户增删改查Dao层MySql实现
*
*/
public class UserDao4MySqlImpl implements UserDao {

/**
* 增加用户
* @param conn
* @param user user对象
*/
public void addUser(Connection conn, User user) {
String sql = "insert into t_user(user_id, user_name, password, contact_tel, email, create_date) "
+ "values(?, ?, ?, ?, ?, ?)";
PreparedStatement pstmt = null;
try {
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, user.getUserId());
pstmt.setString(2, user.getUserName());
pstmt.setString(3, user.getPassword());
pstmt.setString(4, user.getContactTel());
pstmt.setString(5, user.getEmail());
pstmt.setTimestamp(6, new Timestamp(user.getCreateDate().getTime()));
pstmt.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
} finally {
DB.closeStmt(pstmt);
}
}

/**
* 根据userId的集合删除用户
* @param conn
* @param userIdList  userId的集合
*/
public void deleteUsers(Connection conn, String[] userIdList) {
StringBuffer sbfSql = new StringBuffer();
for (int i = 0; i < userIdList.length; i++) {
sbfSql.append("'")
.append(userIdList[i])
.append("'")
.append(",");
}
String sql = "delete from t_user where user_id in (" + sbfSql.substring(0, sbfSql.length()-1) + ")";
Statement stmt = null;
try {
stmt = conn.createStatement();
stmt.executeUpdate(sql);
}catch(SQLException e) {
e.printStackTrace();
}finally {
DB.closeStmt(stmt);
DB.closeConn(conn);
}
}

/**
* 查询所有用户
* @return user对象列表
*/
public List findAllUserList() {
String sql ="select * from t_user where user_id <> 'root' order by user_id ";
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
List userList = new ArrayList();
try {
conn = DB.getConn();
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while (rs.next()) {
User user = new User();
user.setUserId(rs.getString("user_id"));
user.setUserName(rs.getString("user_name"));
user.setPassword(rs.getString("password"));
user.setContactTel(rs.getString("contact_tel"));
user.setEmail(rs.getString("email"));
user.setCreateDate(rs.getTimestamp("create_date"));
userList.add(user);
}
}catch(SQLException e) {
e.printStackTrace();
}finally {
DB.closeRs(rs);
DB.closeStmt(stmt);
DB.closeConn(conn);
}
return userList;
}

/**
* 根据用户id查询用户
* @param userId 用户id
* @return user对象
*/
public User findUserById(String userId) {
String sql = "select * from t_user where user_id=?";
User user = null;
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try  {
conn = DB.getConn();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, userId);
rs = pstmt.executeQuery();
if (rs.next()) {
user = new User();
user.setUserId(rs.getString("user_id"));
user.setUserName(rs.getString("user_name"));
user.setPassword(rs.getString("password"));
user.setContactTel(rs.getString("contact_tel"));
user.setEmail(rs.getString("email"));
user.setCreateDate(rs.getTimestamp("create_date"));
}
}catch(SQLException e) {
e.printStackTrace();
}finally {
DB.closeRs(rs);
DB.closeStmt(pstmt);
DB.closeConn(conn);
}
return user;
}

/**
* 修改用户
* @param conn
* @param user user对象
*/
public void modifyUser(Connection conn, User user) {
String sql = "update t_user set user_name=?, password=?, contact_tel=?, email=? where user_id=?";
PreparedStatement pstmt = null;
try {
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, user.getUserName());
pstmt.setString(2, user.getPassword());
pstmt.setString(3, user.getContactTel());
pstmt.setString(4, user.getEmail());
pstmt.setString(5, user.getUserId());
pstmt.executeUpdate();
}catch(SQLException e) {
e.printStackTrace();
}finally {
DB.closeStmt(pstmt);
}
}

}