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