数据库DB类

package 包名;
//导包
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ResourceBundle;
public class DB {
private Connection conn = null;
private Statement stat = null;
private PreparedStatement pstat = null;
private ResultSet rs = null;
private String driver = null;
private String url = null;
private String userName = null;
private String pass = null;
private static DB db = null;
public static DB getDb() {
if (db == null) {
db = new DB();
}
return db;
}
public DB() {
ResourceBundle rb = ResourceBundle.getBundle("jdbc");
driver = rb.getString("driver");
url = rb.getString("url");
userName = rb.getString("userName");
pass = rb.getString("pass");
}
// 连接数据库
public Connection getConnection() {
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url, userName, pass);
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
public PreparedStatement getPreparedStatement(String sql) { try {
pstat = getConnection().prepareStatement(sql);
} catch (SQLException e) {
e.printStackTrace();
}
return pstat;
}
public int getPUpdate(PreparedStatement pstat) {
int i = 0;
try {
i = pstat.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}
return i;
}
public ResultSet getPquery(PreparedStatement pstat) { try {
rs = pstat.executeQuery();
} catch (SQLException e) {
e.printStackTrace();
}
return rs;
}
public ResultSet getPQuery(String sql) {
try {
rs = getPreparedStatement(sql).executeQuery();
} catch (SQLException e) {
e.printStackTrace();
}
return rs;
}
public void close() {
try {
if (rs != null) {
rs.close();
}
if (pstat != null) {
pstat.close();
}
if (stat != null) {
stat.close();
}
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}。