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dbutils的使用Demo
首先了解一下
Queryrunner.query —————只可以执行select语句。
Queryrunner.update —————只可以接收update,delte,insert语句
BeanHandler ——————返回一个 Bean，结果封装到Bean。只查询第一行。适合根据id查询唯一的一行
BeanListHandler ——————返回List<Bean>所有行，都封装到List，适合于查询多个结果
MapHandler ——————与BeanHandler应，只返回第一行，封装成Map类型 － 也适合于查询一个结果集的 适合于关联查询，且没有匹配的Bean。
MapListHandler ——————与BeanListHandler对应，返回所有，封装成List<Map>类型
ScalarHandler ——————标量- 用于select count(1)|sum|avg|max …一些聚合函数
Demo（MyDataSource.getDataSource() —— 获取 DataSource）
插入数据
1 @org.junit.Test 2 public void Query1() throws Exception 3 { 4 QueryRunner runner=new QueryRunner(MyDataSource.getDataSource()); 5 System.out.println(MyDataSource.getDataSource()); 6 //String sql="INSERT INTO users VALUES (‘U002‘,‘tom‘,‘4321‘ )"; 7 //runner.update(sql); 8 String sql="INSERT INTO users VALUES (?,?,? )"; 9 runner.update(sql,"U003","Jim","123456");10 }
更新数据
1 @org.junit.Test2 public void Query2() throws Exception3 {4 QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());5 //String sql=" UPDATE users SET NAME=‘Kim‘ WHERE NAME=‘jim‘ ";6 //runner.update(sql);7 String sql=" UPDATE users SET NAME=? WHERE NAME=? ";8 runner.update(sql,"lily","Kim");9 }
删除数据
1 @org.junit.Test2 public void Query3() throws Exception3 {4 QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());5 //String sql="DELETE FROM users WHERE NAME=‘lily‘ ";6 //runner.update(sql);7 String sql="DELETE FROM users WHERE NAME=? ";8 runner.update(sql,"tom");9 }
查找数据
1 @org.junit.Test 2 public void Query4() throws Exception 3 { 4 QueryRunner runner=new QueryRunner(MyDataSource.getDataSource()); 5 //String sql="SELECT * FROM users where id =‘U002‘ "; 6 //user u= runner.query(sql, new BeanHandler<user>(user.class)); 7 8 String sql="SELECT * FROM users where id =? "; 9 user u=runner.query(sql, new BeanHandler<user>(user.class),"U002");10 System.out.println(u);11 }
1 @org.junit.Test 2 public void Query5() throws Exception 3 { 4 QueryRunner runner=new QueryRunner(MyDataSource.getDataSource()); 5 String sql="select * from users "; 6 List<user> list= runner.query(sql, new BeanListHandler<user>(user.class)); 7 for(user u:list) 8 { 9 System.out.println(u);10 }11 }
1 @org.junit.Test2 public void Query6() throws Exception3 {4 QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());5 String sql="select Id,name,Pwd from users ";6 Map<String, Object> map= runner.query(sql, new MapHandler());7 System.out.println(map.toString());8 }
1 @org.junit.Test2 public void Query7() throws Exception3 {4 QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());5 String sql="Select * from users ";6 List<Map<String , Object>> list= runner.query(sql, new MapListHandler());7 System.out.println(list);8 }
1 @org.junit.Test2 public void Query8() throws Exception3 {4 QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());5 String sql="select count(*) from Users ";6 Object obj=runner.query(sql, new ScalarHandler());7 int i=Integer.valueOf(obj.toString());8 System.out.println(i);9 }
导入包包括
dbutils的使用Demo
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