Java 开发实例 源码——图书信息管理系统
import com.zhang.model.BookInfo;
import com.zhang.model.BookType;
import com.zhang.model.Operator;
import com.zhang.model.Reader;
import com.zhang.model.User;
public class Dao {
protected static String dbClassName =
"com.microsoft.sqlserver.jdbc.SQLServerDriver";
protected static String dbUrl =
"jdbc:sqlserver://localhost:1433;"
+ "DatabaseName=db_lib;SelectMethod=Cursor";
protected static String dbUser = "sa";
protected static String dbPwd = "zhangyong";
protected static String second = null;
private static Connection conn = null;
//创建数据库连接
private Dao() {
try {
if (conn == null) {
Class.forName(dbClassName).newInstance();
conn = DriverManager.getConnection(dbUrl, dbUser,
dbPwd);
System.out.println("数据库连接成功！");
}
else
return;
} catch (Exception ee) {
ee.printStackTrace();
}
}
//执行查询
private static ResultSet executeQuery(String sql) {
try {
if(conn==null)
new Dao();
return
conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR
_UPDATABLE).executeQuery(sql);
} catch (SQLException e) {
e.printStackTrace();
return null;
} finally {
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