common-dbutils.jar是Apache组织提供的一个对JDBC进行简单封装的开源工具类库,使用它能够简化JDBC应用程序的开发,同时也不会影响程序的性能。
1 import cn.itcast.jdbc.JdbcUtils;
2 import org.apache.commons.dbutils.QueryRunner; 3 import org.apache.commons.dbutils.handlers.*; 4 import org.junit.Test; 5 import java.sql.SQLException; 6 import java.util.List; 7 import java.util.Map; 8 9 public class Demo3 { 10 @Test 11 public void fun1() throws SQLException { 12 QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource()); 13 String sql = "INSERT INTO t_stu VALUES(?,?,?,?)"; 14 Object[] params = {1002,"lisi",99,"female"}; 15 qr.update(sql,params); 16 } 17 @Test 18 public void fun2() throws SQLException { 19 //创建QueryRunner,提供数据库连接池对象 20 QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource()); 21 //给出sql模板 22 String sql = "SELECT * FROM t_stu WHERE sid=?"; 23 //给出参数 24 Object[] params = {1002}; 25 //执行query()方法,需要给出集处理器,即 ResultSetHandler的实现类对象 26 //我们需要给的是BeanHandler,它实现了ResultSetHandler 27 //它需要一个类型,然后它会把rs中的数据封装到指定类型的javabean对象中,然后返回javabean对象 28 Stu stu = qr.query(sql,new BeanHandler<Stu>(Stu.class),params); 29 System.out.println(stu); 30 } 31 //BeanListHandler的应用,它是多行处理器 32 //每行对象一个Stu对象 33 @Test 34 public void fun3() throws Exception{ 35 QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource()); 36 String sql = "SELECT * FROM t_stu"; 37 List<Stu> stuList = qr.query(sql,new BeanListHandler<Stu>(Stu.class)); 38 System.out.println(stuList); 39 } 40 41 //MapHandler的应用,它是单行处理器,把一行转换成一个Map对象 42 @Test 43 public void fun4() throws Exception{ 44 QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource()); 45 String sql = "SELECT * FROM t_stu WHERE sid=?"; 46 Object[] params = {1001}; 47 Map map = qr.query(sql,new MapHandler(),params); 48 System.out.println(map); 49 } 50 51 //MapListHandler,它是多行处理器,把每行都转换成一个Map,即List<Map> 52 @Test 53 public void fun5() throws Exception{ 54 QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource()); 55 String sql = "SELECT * FROM t_stu "; 56 List<Map<String,Object>> mapList = qr.query(sql,new MapListHandler()); 57 System.out.println(mapList); 58 }@Test 59 //ScalarHandler,它是单行单列时使用,最为合适。 60 public void fun6() throws Exception{ 61 QueryRunner qr = new QueryRunner(JdbcUtils.getDataSource()); 62 String sql = "SELECT COUN