BaseDao

:D

//剛開始的時候用的這個 :shock:

public class BaseDao {

private Connection conn;

private PreparedStatement stmt;

private ResultSet rs;

//建立連結

public Connection getConnection(){

try {

Class.forName("com.mysql.jdbc.Driver");

String url="jdbc:mysql://localhost:3306/liubao2";

String user="root";

String password="123456";

conn=DriverManager.getConnection(url, user, password);

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return conn;

}

//關閉連接配接

public void close(){

try {

if(rs!=null){

rs.close();

}

if(stmt!=null){

stmt.close();

}

if(conn!=null){

conn.close();

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

//修改的操作

public boolean executeUpdate(String sql,Object[] parameters){

try {

getConnection();

stmt=conn.prepareStatement(sql);

//占位符 參數指派

if(parameters !=null){

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

stmt.setObject(i+1,parameters[i]);

}

}

int count=stmt.executeUpdate();

close();

return count>0?true:false;

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

return false;

}

}

//查詢的操作 ResultSet

public ResultSet getResultSet(String sql,Object[] parameters){

try {

getConnection();

stmt=conn.prepareStatement(sql);

//占位符 參數指派

if(parameters !=null){

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

stmt.setObject(i+1,parameters[i]);

}

}

rs=stmt.executeQuery();

return rs;

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

return null;

}

}

//将ResultSet --->List<T>

public <T> List<T> executeQuery(String sql,Object[] parameters,Class<T> c){

rs=getResultSet(sql,parameters);

List<T> list=JDBCUtil.convertResultSetToList(c, rs);

close();

return list;

}

//ResultSet ---單個的實體

public <T> T executeSingle(String sql,Object[] parameters,Class<T> c){

rs=getResultSet(sql,parameters);

T t=JDBCUtil.convertResultSetToEntity(c, rs);

return t;

}

//計算總數的方法

public int getCounts(String sql, Object[] parameters) {

// TODO Auto-generated method stub

try {

getConnection();

stmt=conn.prepareStatement(sql);

if(parameters!=null){

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

stmt.setObject(i+1, parameters[i]);

}

}

rs=stmt.executeQuery();

int count=0;

while(rs.next()){

count=rs.getInt(1);

}

close();

return count;

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

return 0;

}

}

}

--奮鬥的劉啊寶