dom读写xml相关回顾

******实体bean******

package com;

import java.io.Serializable;

@SuppressWarnings("serial")
public class UserInfoBean implements Serializable{
 private int userId;
 private String loginName;
 private String loginPass;
 
 public String getLoginName() {
  return loginName;
 }
 public void setLoginName(String loginName) {
  this.loginName = loginName;
 }
 public String getLoginPass() {
  return loginPass;
 }
 public void setLoginPass(String loginPass) {
  this.loginPass = loginPass;
 }
 public int getUserId() {
  return userId;
 }
 public void setUserId(int userId) {
  this.userId = userId;
 }
}

******数据库dao******

package com;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class BaseDAO {
 private static final String DRIVER="com.microsoft.sqlserver.jdbc.SQLServerDriver";
 private static final String URL="jdbc:sqlserver://localhost:1433;databasename=restrant";
 private static final String USER="sa";
 private static final String PWD="sa";
 
 /**
  * 获得数据库连接
  * @return 可用数据库连接
  * @throws Exception
  */
 public Connection getConn()throws Exception{
  Class.forName(DRIVER);
  return DriverManager.getConnection(URL,USER,PWD);
 }
 
 /**
  * 释放资源
  * @param rs 结果集
  * @param ps 命令行对象
  * @param conn 数据库连接
  */
 public void closeAll(ResultSet rs,PreparedStatement ps,Connection conn){
  try {
   if(rs!=null)
     rs.close();
   if(ps!=null)
     ps.close();
   if(conn!=null)
     conn.close();
  } catch (SQLException e){
   e.printStackTrace();
  }
 }
 
 /**
  * 可用执行增，删，改操作，不能用于查询
  * @param sql 预编译的SQL语句
  * @param param 预编译SQL语句中的‘？’参数的字符串数组
  * @return 返回受影响的行数
  */
 public int executeSql(String sql,String[] param){
  Connection conn=null;
  PreparedStatement ps=null;
  int num=0;
  try {
   conn=getConn();
   ps=conn.prepareStatement(sql);
   if(param!=null){
    for(int i=0;i<param.length;i++){
     ps.setString(i+1, param[i]);
    }
   }
   num=ps.executeUpdate();
  }catch (Exception e) {
   e.printStackTrace();
  }finally{
   closeAll(null, ps, conn);
  }
  return num;
 }
}

******具体操作******
package com;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;

public class UserManagerDAO extends BaseDAO {
 public ArrayList<UserInfoBean> searchUser(){
  Connection conn=null;
  PreparedStatement ps=null;
  ResultSet rs=null;
  ArrayList<UserInfoBean> lists=new ArrayList<UserInfoBean>();
  String sql="select * from userinfo";
  try {
   conn=getConn();
   ps=conn.prepareStatement(sql);
   rs=ps.executeQuery();
   while(rs.next()){
    UserInfoBean u=new UserInfoBean();
    u.setUserId(rs.getInt("userid"));
    u.setLoginName(rs.getString("loginname"));
    u.setLoginPass(rs.getString("loginpass"));
    lists.add(u);
   }
  }catch (Exception e) {
   e.printStackTrace();
  }finally{
   closeAll(rs, ps, conn);
  }
  return lists;
 }
}