对数据库的CRUD（增删改查）

package jdbc;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;/** *对数据库的增删改查 * @author HaoWang */public class CRUD {    public static void main(String[] args) {        create();        read();        update();        read();        delete();        read();    }    public static void create() {        Connection conn = null;        Statement st = null;        ResultSet rs = null;        String sql = null;        try {            conn = JdbcUtils.getConnection();            st = conn.createStatement();            sql = "insert into Students(sid,name,sex,birthday) value (4,'wanghao',1,'1987-11-01')";            int i = st.executeUpdate(sql);            System.out.println("i="+i);        } catch (Exception ex) {            System.out.println(ex.toString());        } finally {            JdbcUtils.free(conn, st, rs);        }    }    public static void read() {        Connection conn = null;        Statement st = null;        ResultSet rs = null;        try {            conn = JdbcUtils.getConnection();            st = conn.createStatement();            rs = st.executeQuery("Select * from Students;");            while (rs.next()) {                System.out.println(rs.getObject(1) + "\t" + rs.getObject(2) + "\t" + rs.getObject(3) + "\t" + rs.getObject(4));            }        } catch (SQLException ex) {            System.out.println(ex.toString());        } finally {            JdbcUtils.free(conn, st, rs);        }    }    public static void update() {        Connection conn = null;        Statement st = null;        ResultSet rs = null;        String sql = null;        try {            conn = JdbcUtils.getConnection();            st = conn.createStatement();            sql = "update students set birthday='1987-11-03' where sid=4;";            int i = st.executeUpdate(sql);            System.out.println("i="+i);        } catch (Exception ex) {            System.out.println(ex.toString());        } finally {            JdbcUtils.free(conn, st, rs);        }    }    public static void delete() {        Connection conn = null;        Statement st = null;        ResultSet rs = null;        String sql = null;        try {            conn = JdbcUtils.getConnection();            st = conn.createStatement();            sql = "delete from students where sid>3";            int i = st.executeUpdate(sql);            System.out.println("i="+i);        } catch (Exception ex) {            System.out.println(ex.toString());        } finally {            JdbcUtils.free(conn, st, rs);        }    }}

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