java常用函数(2)

import java.io.*;
import java.sql.*;
import java.util.Properties;
public class Db {
private String driver;
private String url;
private String user;
private String password;
private Connection conn;
private Statement stm;
private ResultSet rs;
public Db(){
this("DBConf.properties");
}
public Db(String conf) {
loadProperties(conf);
setConn();
}
public Connection getConn(){
return this.conn;
}
//handle the properties file to get the informations for connection
private void loadProperties(String conf){
Properties props = new Properties();
try {
props.load(new FileInputStream(conf));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
this.driver = props.getProperty("driver");
this.url = props.getProperty("url");
this.user = props.getProperty("user");
this.password = props.getProperty("password");
}
//implement the Connection
private void setConn(){
try {
Class.forName(driver);
this.conn = DriverManager.getConnection(url,user,password);
} catch(ClassNotFoundException classnotfoundexception) {
classnotfoundexception.printStackTrace();
System.err.println("db: " + classnotfoundexception.getMessage());
} catch(SQLException sqlexception) {
System.err.println("db.getconn(): " + sqlexception.getMessage());
}
}
public void doInsert(String sql) {
try {
Statement statement = conn.createStatement();
int i = stm.executeUpdate(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeInset:" + sqlexception.getMessage());
}
}
public void doDelete(String sql) {
try {
stm = conn.createStatement();
int i = stm.executeUpdate(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeDelete:" + sqlexception.getMessage());
}
}
public void doUpdate(String sql) {
try {
stm = conn.createStatement();
int i = stm.executeUpdate(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeUpdate:" + sqlexception.getMessage());
}
}

public ResultSet doSelect(String sql) {
try {
stm = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
rs = stm.executeQuery(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeQuery: " + sqlexception.getMessage());
}
return rs;
}
public static void main(String[] args){
try{
Db db = new Db();
Connection conn = db.getConn();
if(conn != null && !conn.isClosed()) {
System.out.println("連結成功");
ResultSet rs = db.doSelect("select * from content");
while(rs.next()){
System.out.println(rs.getString(1)+":"+rs.getString(2)+":"+rs.getString(3));
}
rs.close();
conn.close();
}
}catch(SQLException e) {
e.printStackTrace();
}
}
}

DBConf.properties:
driver=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@tdt151:1521:train
user=XX
password=XX