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简单的三层框架以及使用dbutils进行数据库操作(入门)

 
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1.搭建三层框架

1.1.什么是三层框架

三层框架就是将代码简单的分为三层并对某些地方进行必要的封装,方便日后维护,主要分为以下三部分:

界面层(Swing或JSP):主要是界面显示的代码。

业务层(business):主要是处理业务逻辑的代码。

数据访问层(DAO):主要是与数据库交互的代码。

1.2.各层之间如何协作

关系:界面层(调用) à 业务层(调用)à 数据访问层(与数据库交互)

(显示)界面层 ß (结果)业务层 ß (结果)数据访问层

数据传递:各层之间将数据封装成实体类(entity)进行传递。

写入信息:界面层将用户录入的信息封装成实体类对象,然后传给业务层进行相关的业务处理,然后业务层选择需要调用的数据访问层,数据访问层负责将传递过来的实体对像中封装的信息提取出来,并且拼出SQL语句,将信息写入数据库。

显示信息:数据访问层将数据库中的数据提取出来封装成实体对象,如果有多个对象的话继而封装成集合,然后传递给调用它的业务层进行业务处理,业务层再将处理过的实体对象或是集合传递给调用业务层的界面,界面最后将实体对象或是集合中封装的信息提取出来进行显示。

===============================================================================

2.编写实例(省略界面层和业务层)

需要的jar包:数据库直连包,dbutils包

数据库:stuDB

表:USERS

表结构:userId int NOT NULLIDENTITY(1,1) PRIMARY KEY,

userName nvarchar(20) NOT NULL,

password nvarchar(20) NOT NULL,

realName nvarchar(20) ,

sex nvarchar(2)

=========================================================

实体类:UsersEntity

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package com.saga.entity;

/**

*USERS表的实体类

*@author saga1320

*/

public class UsersEntity {

private int userId;

private String userName;

private String password;

private String realName;

private String sex;

public UsersEntity() {

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public String getRealName() {

return realName;

}

public void setRealName(String realName) {

this.realName = realName;

}

public String getSex() {

return sex;

}

public void setSex(String sex) {

this.sex = sex;

}

public int getUserId() {

return userId;

}

public void setUserId(int userId) {

this.userId = userId;

}

public String getUserName() {

return userName;

}

public void setUserName(String userName) {

this.userName = userName;

}

}

package com.saga.entity;

/**

*USERS表的实体类

*@author saga1320

*/

public class UsersEntity {

private int userId;

private String userName;

private String password;

private String realName;

private String sex;

public UsersEntity() {

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public String getRealName() {

return realName;

}

public void setRealName(String realName) {

this.realName = realName;

}

public String getSex() {

return sex;

}

public void setSex(String sex) {

this.sex = sex;

}

public int getUserId() {

return userId;

}

public void setUserId(int userId) {

this.userId = userId;

}

public String getUserName() {

return userName;

}

public void setUserName(String userName) {

this.userName = userName;

}

}

===============================================================

2.1.没有使用dbutils的数据访问层(只需直连包)

首先,创建所有数据访问类的抽象基类BaseDAO

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package com.saga.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

/**

* 所有数据访问类的基类,其他数据访问类需继承此类

*@author saga1320

*/

public abstract class BaseDAO {

//数据库连接驱动名

private static final String DRIVERNAME

="com.microsoft.sqlserver.jdbc.SQLServerDriver";

//数据库连接URL

private static final String RUL

="jdbc:sqlserver://localhost:1433;databaseName=stuDB";

//数据库用户名

private static final String UNAME="sa";

//密码

private static final String PWD="";

private Connection conn=null;

/**

* 建立数据库连接

* @throws ClassNotFoundException

* @throws SQLException

*/

private void getConnection()

throws ClassNotFoundException,SQLException{

Class.forName(DRIVERNAME);

conn=DriverManager.getConnection(RUL,UNAME,PWD);

}

public BaseDAO() {

super();

}

/**

* 执行增,删,改,(带参数)

* @param strSql sql语句

* @param param 参数

* @return sql语句所影响的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

protected int executeUpdate(String strSql,Object[] param)

throws ClassNotFoundException,SQLException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

for (int i = 0; i < param.length; i++) {

pstat.setObject(i+1,param[i]);

}

return pstat.executeUpdate();

}

/**

* 执行增,删,改,(不带参数)

* @param strSql sql语句

* @return sql语句所影响的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

protected int executeUpdate(String strSql)

throws ClassNotFoundException,SQLException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

return pstat.executeUpdate();

}

/**

* 带参数查询

* @param strSql sql语句

* @param param 参数

* @return ResultSet 结果集

* @throws ClassNotFoundException

* @throws SQLException

*/

protected ResultSet executeQuery(String strSql,Object[] param)

throws SQLException,ClassNotFoundException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

for (int i = 0; i < param.length; i++) {

pstat.setObject(i+1,param[i]);

}

return pstat.executeQuery();

}

/**

* 无参查询

* @param strSql sql语句

* @param param 参数

* @return ResultSet 结果集

* @throws SQLException

* @throws ClassNotFoundException

*/

protected ResultSet executeQuery(String strSql)

throws SQLException,ClassNotFoundException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

return pstat.executeQuery();

}

/**

* 关闭数据库连接

* @throws SQLException

*/

protected void closeConnection() throws SQLException{

if(conn!=null){

if(!conn.isClosed()){

conn.close();

}

}

}

}

package com.saga.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

/**

* 所有数据访问类的基类,其他数据访问类需继承此类

*@author saga1320

*/

public abstract class BaseDAO {

//数据库连接驱动名

private static final String DRIVERNAME

="com.microsoft.sqlserver.jdbc.SQLServerDriver";

//数据库连接URL

private static final String RUL

="jdbc:sqlserver://localhost:1433;databaseName=stuDB";

//数据库用户名

private static final String UNAME="sa";

//密码

private static final String PWD="";

private Connection conn=null;

/**

* 建立数据库连接

* @throws ClassNotFoundException

* @throws SQLException

*/

private void getConnection()

throws ClassNotFoundException,SQLException{

Class.forName(DRIVERNAME);

conn=DriverManager.getConnection(RUL,UNAME,PWD);

}

public BaseDAO() {

super();

}

/**

* 执行增,删,改,(带参数)

* @param strSql sql语句

* @param param 参数

* @return sql语句所影响的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

protected int executeUpdate(String strSql,Object[] param)

throws ClassNotFoundException,SQLException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

for (int i = 0; i < param.length; i++) {

pstat.setObject(i+1,param[i]);

}

return pstat.executeUpdate();

}

/**

* 执行增,删,改,(不带参数)

* @param strSql sql语句

* @return sql语句所影响的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

protected int executeUpdate(String strSql)

throws ClassNotFoundException,SQLException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

return pstat.executeUpdate();

}

/**

* 带参数查询

* @param strSql sql语句

* @param param 参数

* @return ResultSet 结果集

* @throws ClassNotFoundException

* @throws SQLException

*/

protected ResultSet executeQuery(String strSql,Object[] param)

throws SQLException,ClassNotFoundException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatement pstat=conn.prepareStatement(strSql);

for (int i = 0; i < param.length; i++) {

pstat.setObject(i+1,param[i]);

}

return pstat.executeQuery();

}

/**

* 无参查询

* @param strSql sql语句

* @param param 参数

* @return ResultSet 结果集

* @throws SQLException

* @throws ClassNotFoundException

*/

protected ResultSet executeQuery(String strSql)

throws SQLException,ClassNotFoundException{

if(conn==null || conn.isClosed()){

this.getConnection();

}

PreparedStatementpstat=conn.prepareStatement(strSql);

return pstat.executeQuery();

}

/**

* 关闭数据库连接

* @throws SQLException

*/

protected void closeConnection() throws SQLException{

if(conn!=null){

if(!conn.isClosed()){

conn.close();

}

}

}

}

接着,创建USERS表的数据访问类:USersDAO

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package com.saga.dao;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import com.saga.entity.UsersEntity;

/**

*USERS表的数据访问类,继承BaseDAO

*@author saga1320

*/

public class UsersDAO extends BaseDAO{

public UsersDAO(){

super();

}

/**

* 向USERS表中添加一条数据

* @param user UsersEntity封装了数据信息

* @return int 添加记录的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

public int insertUser(UsersEntity user)

throws ClassNotFoundException,SQLException{

int = 0;

String strSql="INSERT INTO USERS VALUES(?,?,?,?)";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

/**

* 根据userId修改USERS信息

* @param user UsersEntity封装了数据信息

* @return int 修改记录的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

public int updateUsersById(UsersEntity user)

throws ClassNotFoundException, SQLException{

int = 0;

String strSql="UPDATE USERS SET userName=?, password=?, realName=?,sex=? WHEREuserId=?";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex(),

user.getUserId()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

/**

* 查询USERS表的所有信息

* @return List<UsersEntity> UsersEntity实体的泛型集合

* @throws SQLException

* @throws ClassNotFoundException

*/

public List<UsersEntity> getAllUsers()

throws SQLException,ClassNotFoundException{

List<UsersEntity> listUsers = newArrayList<UsersEntity>();

String strSql="SELECT * FROM USERS";

ResultSet rs=this.executeQuery(strSql);

while(rs.next()){

UsersEntity user=newUsersEntity();

user.setUserId(rs.getInt("userId"));

user.setUserName(rs.getString("userName"));

user.setPassword(rs.getString("password"));

user.setRealName(rs.getString("RealName"));

user.setSex(rs.getString("sex"));

listUsers.add(user);

}

super.closeConnection();

return listUsers;

}

/**

* 根据userId查询USERS表信息

* @return UsersEntity

* @throws SQLException

* @throws ClassNotFoundException

*/

public UsersEntity getUserById(String userId)

throws SQLException,ClassNotFoundException{

UsersEntity User = null;

String strSql="SELECT * FROM USERS WHERE userId=?";

ResultSet rs=this.executeQuery(strSql, new Object [] {userId});

if(rs.next()){

user=new UsersEntity();

user.setUserId(rs.getInt("userId"));

user.setUserName(rs.getString("userName"));

user.setPassword(rs.getString("password"));

user.setRealName(rs.getString("RealName"));

user.setSex(rs.getString("sex"));

}

super.closeConnection();

return User;

}

}

package com.saga.dao;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import com.saga.entity.UsersEntity;

/**

*USERS表的数据访问类,继承BaseDAO

*@author saga1320

*/

public class UsersDAO extends BaseDAO {

public UsersDAO(){

super();

}

/**

* 向USERS表中添加一条数据

* @param user UsersEntity封装了数据信息

* @return int 添加记录的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

public int insertUser(UsersEntity user)

throws ClassNotFoundException,SQLException{

int = 0;

String strSql="INSERT INTO USERS VALUES(?,?,?,?)";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

/**

* 根据userId修改USERS信息

* @param user UsersEntity封装了数据信息

* @return int 修改记录的行数

* @throws SQLException

* @throws ClassNotFoundException

*/

public int updateUsersById(UsersEntity user)

throws ClassNotFoundException,SQLException{

int = 0;

String strSql="UPDATE USERS SET userName=?, password=?, realName=?,sex=? WHERE userId=?";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex(),

user.getUserId()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

/**

* 查询USERS表的所有信息

* @return List<UsersEntity> UsersEntity实体的泛型集合

* @throws SQLException

* @throws ClassNotFoundException

*/

public List<UsersEntity> getAllUsers()

throws SQLException,ClassNotFoundException{

List<UsersEntity> listUsers = new ArrayList<UsersEntity>();

String strSql="SELECT * FROM USERS";

ResultSet rs=this.executeQuery(strSql);

while(rs.next()){

UsersEntity user=newUsersEntity();

user.setUserId(rs.getInt("userId"));

user.setUserName(rs.getString("userName"));

user.setPassword(rs.getString("password"));

user.setRealName(rs.getString("RealName"));

user.setSex(rs.getString("sex"));

listUsers.add(user);

}

super.closeConnection();

return listUsers;

}

/**

* 根据userId查询USERS表信息

* @return UsersEntity

* @throws SQLException

* @throws ClassNotFoundException

*/

public UsersEntity getUserById(String userId)

throws SQLException,ClassNotFoundException{

UsersEntity User = null;

String strSql="SELECT * FROM USERS WHERE userId=?";

ResultSet rs=this.executeQuery(strSql, new Object [] {userId});

if(rs.next()){

user=new UsersEntity();

user.setUserId(rs.getInt("userId"));

user.setUserName(rs.getString("userName"));

user.setPassword(rs.getString("password"));

user.setRealName(rs.getString("RealName"));

user.setSex(rs.getString("sex"));

}

super.closeConnection();

return User;

}

}

最后,只需要在业务层调用这些方法就行了。

==============================================================================================================================================================

2.2.使用dbutils的数据访问层(需直连包,dbutils包)

首先,创建所有数据访问类的抽象基类BaseDAO

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package com.saga.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

import java.util.List;

importorg.apache.commons.dbutils.DbUtils;

importorg.apache.commons.dbutils.QueryRunner;

importorg.apache.commons.dbutils.ResultSetHandler;

public abstract class BaseDAO {

private static final String DRIVERNAME

="com.microsoft.sqlserver.jdbc.SQLServerDriver";

private static final String URL

="jdbc:sqlserver://localhost:1433;databaseName=stuDB";

private static final String UID = "sa";

private static final String PWD = "";

private Connection conn = null;

public BaseDAO() {

super();

}

------------------------------------------------------------------------------------------------

/**

* 建立数据库连接

* @throws SQLException

*/

private void getConnection() throws SQLException{

DbUtils.loadDriver(DRIVERNAME);

conn = DriverManager.getConnection(URL,UID,PWD);

}

/**

* 关闭数据库连接

* @throws SQLException

*/

protected void closeConnection() throws SQLException{

DbUtils.close(conn);

}

=================================================

/**

* 带参数的查询

* @param strSql 查询语句

* @param param 参数

* @param rsh ResultSetHandler接口的实现对象

* @return 查询结果的集合

* @throws SQLException

*/

protected List executeQuery(String strSql, Object[] param,ResultSetHandler rsh) throws SQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return (List) runner.query(conn, strSql, param, rsh);

}

/**

* 不带参数的查询

* @param strSql 查询语句

* @param rsh ResultSetHandler接口的实现对象

* @return 查询结果的集合

* @throws SQLException

*/

protected List executeQuery(String strSql, ResultSetHandler rsh) throwsSQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return (List) runner.query(conn, strSql, rsh);

}

/**

* 查询一条记录

* @param strSql 查询语句

* @param param 参数

* @param rsh ResultSetHandler接口的实现对象

* @return 记录对应的实体

* @throws SQLException

*/

protected Object executeQueryObject(String strSql, Object[] param,ResultSetHandler rsh) throws SQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return runner.query(conn, strSql,param, rsh);

}

/**

* 带参数的增,删,改

* @param strSql 增,删,改的执行语句

* @param param 参数

* @return 影响的记录数

* @throws SQLException

*/

protected int executeUpdate(String strSql, Object[] param) throwsSQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return runner.update(conn, strSql, param);

}

/**

* 不带参数的增,删,改

* @param strSql 增,删,改的执行语句

* @return 影响的记录数

* @throws SQLException

*/

protected int executeUpdate(String strSql) throws SQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return runner.update(conn, strSql);

}

}

package com.saga.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

import java.util.List;

import org.apache.commons.dbutils.DbUtils;

importorg.apache.commons.dbutils.QueryRunner;

importorg.apache.commons.dbutils.ResultSetHandler;

public abstract class BaseDAO {

private static final String DRIVERNAME

= "com.microsoft.sqlserver.jdbc.SQLServerDriver";

private static final String URL

="jdbc:sqlserver://localhost:1433;databaseName=stuDB";

private static final String UID = "sa";

private static final String PWD = "";

private Connection conn = null;

public BaseDAO() {

super();

}

/**

* 建立数据库连接

* @throws SQLException

*/

private void getConnection() throws SQLException{

DbUtils.loadDriver(DRIVERNAME);

conn = DriverManager.getConnection(URL,UID,PWD);

}

/**

* 关闭数据库连接

* @throws SQLException

*/

protected void closeConnection() throws SQLException{

DbUtils.close(conn);

}

/**

* 带参数的查询

* @param strSql 查询语句

* @param param 参数

* @param rsh ResultSetHandler接口的实现对象

* @return 查询结果的集合

* @throws SQLException

*/

protected List executeQuery(String strSql, Object[] param,ResultSetHandler rsh) throws SQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return (List) runner.query(conn, strSql, param, rsh);

}

/**

* 不带参数的查询

* @param strSql 查询语句

* @param rsh ResultSetHandler接口的实现对象

* @return 查询结果的集合

* @throws SQLException

*/

protected List executeQuery(String strSql, ResultSetHandler rsh) throwsSQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return (List) runner.query(conn, strSql, rsh);

}

/**

* 查询一条记录

* @param strSql 查询语句

* @param param 参数

* @param rsh ResultSetHandler接口的实现对象

* @return 记录对应的实体

* @throws SQLException

*/

protected Object executeQueryObject(String strSql, Object[] param,ResultSetHandler rsh) throws SQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return runner.query(conn, strSql,param, rsh);

}

/**

* 带参数的增,删,改

* @param strSql 增,删,改的执行语句

* @param param 参数

* @return 影响的记录数

* @throws SQLException

*/

protected int executeUpdate(String strSql, Object[] param) throwsSQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return runner.update(conn, strSql, param);

}

/**

* 不带参数的增,删,改

* @param strSql 增,删,改的执行语句

* @return 影响的记录数

* @throws SQLException

*/

protected int executeUpdate(String strSql) throws SQLException{

if (conn == null || conn.isClosed()) {

this.getConnection();

}

QueryRunner runner = new QueryRunner();

return runner.update(conn, strSql);

}

}

接着,创建USERS表的数据访问类:USersDAO

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package com.saga.dao;

import java.sql.SQLException;

import java.util.List;

importorg.apache.commons.dbutils.ResultSetHandler;

importorg.apache.commons.dbutils.handlers.BeanHandler;

importorg.apache.commons.dbutils.handlers.BeanListHandler;

import com.saga.entity.UsersEntity;

public class UsersDAO extends BaseDAO{

public UsersDAO() {

super();

// TODO Auto-generated constructor stub

}

/**

* 得到USERS表所有的记录

* @return List UserEntity的集合

* @throws SQLException

*/

public List getAllUsers() throws SQLException{

List listUsers = null;

String strSql = "SELECT * FROM USERS";

ResultSetHandler rsh = new BeanListHandler(UsersEntity.class);

listUsers = super.executeQuery(strSql, rsh);

super.closeConnection();

return listUsers;

}

/**

* 根据USERS编号得到USERS信息

* @param userId USERS编号

* @return UsersEntity

* @throws SQLException

*/

public UsersEntity getUsersById(String userId) throws SQLException{

UsersEntity user = null;

String strSql = "SELECT * FROMUSERS WHERE userId = ?";

ResultSetHandler rsh = new BeanHandler(UsersEntity.class);

user = (UsersEntity) super.executeQueryObject(strSql, new Object[]{userId}, rsh);

super.closeConnection();

return user;

}

/**

* 向USERS表添加一条记录

* @param user UsersEntity对象

* @return int

* @throws SQLException

*/

public int insertUser(UsersEntity user)throws SQLException{

int i = 0;

String strSql = "INSERT INTO USERS VALUES(?,?,?,?)";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

/**

* 根据USERS编号修改USERS信息

* @param user UsersEntity对象

* @return int

* @throws SQLException

*/

public int updateUserById(UsersEntityuser) throws SQLException{

int i = 0;

String strSql = "UPDATE USERS SET userName=?, password=?,realName=?, sex=? WHEREuserId=?";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex(),

user.getUserId()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

}

package com.saga.dao;

import java.sql.SQLException;

import java.util.List;

import org.apache.commons.dbutils.ResultSetHandler;

importorg.apache.commons.dbutils.handlers.BeanHandler;

importorg.apache.commons.dbutils.handlers.BeanListHandler;

import com.saga.entity.UsersEntity;

public class UsersDAO extends BaseDAO {

public UsersDAO() {

super();

// TODO Auto-generated constructor stub

}

/**

* 得到USERS表所有的记录

* @return List UserEntity的集合

* @throws SQLException

*/

public List getAllUsers() throws SQLException{

List listUsers = null;

String strSql = "SELECT * FROM USERS";

ResultSetHandler rsh = new BeanListHandler(UsersEntity.class);

listUsers = super.executeQuery(strSql, rsh);

super.closeConnection();

return listUsers;

}

/**

* 根据USERS编号得到USERS信息

* @param userId USERS编号

* @return UsersEntity

* @throws SQLException

*/

public UsersEntity getUsersById(String userId) throws SQLException{

UsersEntity user = null;

String strSql = "SELECT * FROM USERS WHERE userId = ?";

ResultSetHandler rsh = new BeanHandler(UsersEntity.class);

user = (UsersEntity)super.executeQueryObject(strSql, new Object []{userId}, rsh);

super.closeConnection();

return user;

}

/**

* 向USERS表添加一条记录

* @param user UsersEntity对象

* @return int

* @throws SQLException

*/

public int insertUser(UsersEntity user) throws SQLException{

int i = 0;

String strSql = "INSERT INTO USERS VALUES(?,?,?,?)";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

/**

* 根据USERS编号修改USERS信息

* @param user UsersEntity对象

* @return int

* @throws SQLException

*/

public int updateUserById(UsersEntity user) throws SQLException{

int i = 0;

String strSql = "UPDATE USERS SET userName=?, password=?,realName=?, sex=? WHERE userId=?";

Object [] param = new Object [] {

user.getUserName(),

user.getPassword(),

user.getRealName(),

user.getSex(),

user.getUserId()

};

i = super.executeUpdate(strSql, param);

super.closeConnection();

return i;

}

}

最后,只需要在业务层调用这些方法就行了。

但是,如果使用dbutils包的话,需要注意以下几点:

a、实体类属性的名称要与库中字段的名字一致,否则无法查到结果。

b、ResultSetHandler rsh = 接口的实现类

如果返回对象的话使用newBeanHandler();

如果返回的是集合的话使用 newBeanListHandler();

这里只介绍了dbutils的一种基本用法,至于dbutils的其他用法,有兴趣的朋友可以参考一下dbutils帮助文档。

本文来自CSDN博客,转载请标明出处:http://blog.csdn.net/saga1320/archive/2008/11/09/3257994.aspx

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