s1(java)项目实战（固定资产管理）（tools

package tools;

/** * <p>Title: </p> * * <p>Description: </p> * * <p>Copyright: Copyright (c) 2007</p> * * <p>Company: </p> * * @author not attributable * @version 1.0 */import java.sql.*;import java.util.*;

public class DBConnection {    private Connection con = null;    private String url;    private String user;    private String pwd;    private Statement st = null;    private ResultSet rs = null;

   public DBConnection() {        this.url = "jdbc:odbc:asset";        this.user = "";        this.pwd = "";    }

    //查询select    public Vector select(String sql) {        Vector content = new Vector();        try {            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");            con = DriverManager.getConnection(url, user, pwd);            st = con.createStatement();            rs = st.executeQuery(sql);            ResultSetMetaData rsmd = rs.getMetaData();            int Columns = rsmd.getColumnCount();            while (rs.next()) {                Vector v = new Vector(Columns);                for (int i = 1; i <= Columns; i++) {                    v.add(i - 1, rs.getString(i));                }                content.add(v);            }        } catch (Exception e1) {            System.out.println("Exception in DATAConnection in select::" +                               e1.getMessage());            e1.printStackTrace();        } finally {            try {                if (rs != null) {                    rs.close();                }                if (st != null) {                    st.close();                }                if (con != null) {                    con.close();                }            } catch (Exception e11) {                System.out.println("Exception in DATAConnection in select::" +                                   e11.getMessage());                e11.printStackTrace();            }        }        return content;    }

    //判断结果集是否为空    public boolean isNull(String sql) {        boolean flags = false;        try {            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");            con = DriverManager.getConnection(url, user, pwd);            st = con.createStatement();            rs = st.executeQuery(sql);            flags = rs.next();        } catch (Exception e2) {            System.out.println("Exception in DATAConnection in isNull::" +                               e2.getMessage());            e2.printStackTrace();        } finally {            try {                if (rs != null) {                    rs.close();                }                if (st != null) {                    st.close();                }                if (con != null) {                    con.close();                }            } catch (Exception e12) {                System.out.println("Exception in DATAConnection in select::" +                                   e12.getMessage());                e12.printStackTrace();            }        }        return flags;

    }

    //update/delete/insert等SQL命令    public String update(int style, String sql) {        String resultstr = null;        try {            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");            con = DriverManager.getConnection(url, user, pwd);            st = con.createStatement();            int count = st.executeUpdate(sql);            if (count > 0) {                if (style == 1) {                    resultstr = "修改了" + count + "条记录";                } else if (style == 2) {                    resultstr = "删除了" + count + "条记录";                } else if (style == 3) {                    resultstr = "插入了" + count + "条记录";                } else {                    resultstr = "操作失败";                }            }        } catch (Exception e3) {            System.out.println("Exception in DATAConnection in update::" +                               e3.getMessage());            e3.printStackTrace();        } finally {            try {                if (st != null) {                    st.close();                }                if (con != null) {                    con.close();                }            } catch (Exception e13) {                System.out.println("Exception in DATAConnection in select::" +                                   e13.getMessage());                e13.printStackTrace();            }        }        return resultstr;    }

    //得到字段名列表    public String[] getColumnname(String sql) {        String[] s = null;        try {            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");            con = DriverManager.getConnection(url, user, pwd);            st = con.createStatement();            rs = st.executeQuery(sql);            ResultSetMetaData rsmd = rs.getMetaData();            int Columns = rsmd.getColumnCount();            s = new String[Columns];            for (int i = 1; i <= Columns; i++) {                s[i - 1] = rsmd.getColumnName(i);            }        } catch (Exception e4) {            System.out.println("Exception in DATAConnection in getColumnname::" +                               e4.getMessage());            e4.printStackTrace();        } finally {            try {                if (rs != null) {                    rs.close();                }                if (st != null) {                    st.close();                }                if (con != null) {                    con.close();                }            } catch (Exception e14) {                System.out.println("Exception in DATAConnection in closeall::" +                                   e14.getMessage());                e14.printStackTrace();            }        }        return s;    }}