java中QueryRunner类实现增删改查详解.docVIP

JAVA中DBUtils的QueryRunner类实现增删改 一.QueryRunner类实现增删改 ? ?? ??? ??? ???public static void main(String[] args) throws Exception{ //使用自己的工具类，获取数据库的连接对象 Connection conn = MyJDBCUtils.getConnection(); //创建QueryRunner类对象 QueryRunner qr = new QueryRunner(); String sql = UPDATE gjp_ledger set money=? , ldesc=? where lid=?; Object[] params = {998,买钻石,3}; int result = qr.update(conn, sql, params); System.out.println(result); DbUtils.close(conn); } 二.QueryRunner类获取查询结果集ResultSetHandler ? ? 1.常用Handler *?ArrayHandler 将结果集第一行转成对象数组 ? ??? ??? ??? ??? ??public static void main(String[] args) throws Exception{ ? ??Connection conn = MyJDBCUtils.getConnection(); ? ??String sql = SELECT * FROM gjp_ledger where lid=?; ? ??//结果集处理方式，ArrayHandler 第一行转成对象数组 ? ??QueryRunner qr = new QueryRunner(); ? ??Object[] objects = qr.query(conn, sql, new ArrayHandler(),3); ? ??for(Object obj : objects){ ? ??System.out.println(obj); ? ??} ? ??} *?ArrayListHandler 将结果集中的每一行数据都转成一个对象数组，再将转成的多个对象数组存放到List中 ? ??? ??? ??? ??? ??? ??public static void main(String[] args) throws Exception{ ? ??? ??Connection conn = MyJDBCUtils.getConnection(); String sql = SELECT * FROM gjp_ledger; QueryRunner qr = new QueryRunner(); //执行query方法，传递连接对象，SQL语句，结果集处理方式ArrayListHandler ListObject[] list = qr.query(conn, sql, new ArrayListHandler()); for(Object[] objects : list){ for(Object obj : objects){ System.out.print(obj+ ); } System.out.println(); } } *?BeanHandler 将结果集第一行数据封装到一个对应的业务类实例中 ? ??? ??? ??? ??? ??? ??? ??? ???(1): 定义业务数据类Ledger(实体类，javaBean) public class Ledger { //要生成空参、有参构造、set和get方法、toString方法 private int lid; private String parent; private double money; private int sid; private String account; private String createtime; private String ldesc; } * (2)测试案例代码 public static void main(String[] args) throws Exception{ Connection conn = MyJDBCUtils.getConnection(); String sql = SELECT * FROM gjp_ledger; QueryRunner qr = new QueryRunner(); //BeanHandler泛型 ，构造方法(和反射有关系的对象) Ledger legder = qr.query(con