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#java宿舍表

本文介绍了一个使用Java实现的建筑管理系统的DAO层代码细节，包括获取建筑列表、获取单个建筑信息、添加、更新及删除建筑记录等功能，并展示了如何通过SQL语句与数据库进行交互。

[java]代码库package com.dao;

import com.db.DBHelper;

import com.bean.BuildingBean;

import java.util.*;

import java.sql.*;

public class BuildingDao {

//获取列表

public List GetList(String strwhere,String strorder){

String sql="select * from Building";

if(!(isInvalid(strwhere)))

{

sql+=" where "+strwhere;

}

if(!(isInvalid(strorder)))

{

sql+=" order by "+strorder;

}

Statement stat = null;

ResultSet rs = null;

Connection conn = new DBHelper().getConn();

List list=new ArrayList();

try{

stat = conn.createStatement();

rs = stat.executeQuery(sql);

while(rs.next()){

BuildingBean cnbean=new BuildingBean();

cnbean.setBuilding_ID(rs.getInt("Building_ID"));

cnbean.setBuilding_Name(rs.getString("Building_Name"));

cnbean.setBuilding_Introduction(rs.getString("Building_Introduction"));

list.add(cnbean);

}

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

if (conn != null)

conn.close();

if (stat != null)

stat.close();

if (rs != null)

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

return list;

}

//获取指定ID的实体Bean

public BuildingBean GetBean(int id){

String sql="select * from Building where Building_ID="+id;

Statement stat = null;

ResultSet rs = null;

Connection conn = new DBHelper().getConn();

BuildingBean cnbean=new BuildingBean();

try{

stat = conn.createStatement();

rs = stat.executeQuery(sql);

while(rs.next()){

cnbean.setBuilding_ID(rs.getInt("Building_ID"));

cnbean.setBuilding_Name(rs.getString("Building_Name"));

cnbean.setBuilding_Introduction(rs.getString("Building_Introduction"));

}

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

if (conn != null)

conn.close();

if (stat != null)

stat.close();

if (rs != null)

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

return cnbean;

}

//添加

public void Add(BuildingBean cnbean){

String sql="insert into Building (";

sql+="Building_Name,Building_Introduction";

sql+=") values(";

sql+="'"+cnbean.getBuilding_Name()+"','"+cnbean.getBuilding_Introduction()+"'";

sql+=")";

Statement stat = null;

ResultSet rs = null;

Connection conn = new DBHelper().getConn();

try{

stat = conn.createStatement();

stat.executeUpdate(sql);

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

if (conn != null)

conn.close();

if (stat != null)

stat.close();

if (rs != null)

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

//修改

public void Update(BuildingBean cnbean){

String sql="update Building set ";

sql+="Building_Name='"+cnbean.getBuilding_Name()+"',";

sql+="Building_Introduction='"+cnbean.getBuilding_Introduction()+"'";

sql+=" where Building_ID='"+cnbean.getBuilding_ID()+"'";

Statement stat = null;

ResultSet rs = null;

Connection conn = new DBHelper().getConn();

try{

stat = conn.createStatement();

stat.executeUpdate(sql);

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

if (conn != null)

conn.close();

if (stat != null)

stat.close();

if (rs != null)

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

//删除

public void Delete(String strwhere){

String sql="delete Building where ";

sql+=strwhere;

Statement stat = null;

ResultSet rs = null;

Connection conn = new DBHelper().getConn();

try{

stat = conn.createStatement();

stat.executeUpdate(sql);

} catch (SQLException e) {

e.printStackTrace();

} finally {

try {

if (conn != null)

conn.close();

if (stat != null)

stat.close();

if (rs != null)

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

//判断是否空值

private boolean isInvalid(String value) {

return (value == null || value.length() == 0);

}

//测试

public static void main(String[] args) {

System.out.println("");

}

[代码运行效果截图]