黑马day12 DbUtils的介绍
2015-07-02 15:44
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简介:
DbUtils为不喜欢hibernate框架的钟爱,它是线程安全的,不存在并发问题。
使用步骤:
1. QueryRunner runner=new QueryRunner(这里写数据源...如c3p0的数据元new ComboPooledDataSource()或者dbcp的数据元);
2.使用runner的方法如果要增删改就使用update(String sql,Object ... params)
sql:传递的sql语句
params:可变参数,为sql语句中的?所代替的参数
使用runner的方法要查询使用runner的query(String sql,ResultSetHandle handle ,Object ... params)
sql:传递的sql语句
handle :一个接口要是实现其中的handle方法
params:可变参数,为sql语句中的?所代替的参数
案例:
mysql> select * from account;
+----+--------+-------+
| id | name | money |
+----+--------+-------+
| 1 | 李卫康 | 9000 |
+----+--------+-------+
1 row in set
mysql> select * from account;
+----+--------+-------+
| id | name | money |
+----+--------+-------+
| 1 | 李卫康 | 10000 |
+----+--------+-------+
1 row in set
mysql> select * from account;
+----+--------+-------+
| id | name | money |
+----+--------+-------+
| 1 | 李卫康 | 10000 |
| 5 | 程崇树 | 5000 |
+----+--------+-------+
DbUtils为不喜欢hibernate框架的钟爱,它是线程安全的,不存在并发问题。
使用步骤:
1. QueryRunner runner=new QueryRunner(这里写数据源...如c3p0的数据元new ComboPooledDataSource()或者dbcp的数据元);
2.使用runner的方法如果要增删改就使用update(String sql,Object ... params)
sql:传递的sql语句
params:可变参数,为sql语句中的?所代替的参数
使用runner的方法要查询使用runner的query(String sql,ResultSetHandle handle ,Object ... params)
sql:传递的sql语句
handle :一个接口要是实现其中的handle方法
params:可变参数,为sql语句中的?所代替的参数
案例:
package com.itheima.dbutils; import java.sql.ResultSet; import java.sql.SQLException; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.ResultSetHandler; import org.junit.Test; import com.itheima.domain.Account; import com.mchange.v2.c3p0.ComboPooledDataSource; public class DbUtilsDemo1 { @Test public void add() throws SQLException{ QueryRunner runner=new QueryRunner(new ComboPooledDataSource()); runner.update("insert into account values(null,?,?)", "韩玮",7000); } @Test public void update() throws SQLException{ QueryRunner runner=new QueryRunner(new ComboPooledDataSource()); runner.update("update account set money=? where name=?", 9000,"李卫康"); } @Test public void delete() throws SQLException{ QueryRunner runner=new QueryRunner(new ComboPooledDataSource()); runner.update("delete from account where name=?","韩玮"); } @Test public void query() throws SQLException{ final Account account=new Account(); QueryRunner runner=new QueryRunner(new ComboPooledDataSource()); runner.query("select * from account where name =?", new ResultSetHandler<Account>(){ @Override public Account handle(ResultSet rs) throws SQLException { while(rs.next()){ account.setId(rs.getInt("id")); account.setName(rs.getString("name")); account.setMoney(rs.getDouble("money")); } return account; } }, "李卫康"); System.out.println(account.getMoney()); } }运行结果查询数据库:
mysql> select * from account;
+----+--------+-------+
| id | name | money |
+----+--------+-------+
| 1 | 李卫康 | 9000 |
+----+--------+-------+
1 row in set
mysql> select * from account;
+----+--------+-------+
| id | name | money |
+----+--------+-------+
| 1 | 李卫康 | 10000 |
+----+--------+-------+
1 row in set
mysql> select * from account;
+----+--------+-------+
| id | name | money |
+----+--------+-------+
| 1 | 李卫康 | 10000 |
| 5 | 程崇树 | 5000 |
+----+--------+-------+
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