Apache-DBUtils实现mysql数据库的CRUD操作-白红宇

Apache-DBUtils实现mysql数据库的CRUD操作

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发布时间：2019-03-15

本文共 3525 字，大约阅读时间需要 11 分钟。

Apache-DBUtils实现CRUD操作

commons-dbutils是Apache组织提供的一个开源JDBC工具库类，封装了针对于数据库的增删改查操作

QueryRunner测试插入数据

public void testInsert() throws Exception {        Connection conn = JDBCUtils.getConnection1();        QueryRunner runner = new QueryRunner();        String sql = "insert into customers(name,email,birth)values(?,?,?)";        runner.update(conn,sql,"古德","gude@126.com","1987-08-08");    }

QueryRunner测试插入数据

BeanHandler：是ResultSetHandler接口的实现类，用于封装表中的一条记录

public void testInsert1() {        Connection conn = null;        try {            conn = JDBCUtils.getConnection1();            QueryRunner runner = new QueryRunner();            String sql = "select id,name,email,birth from customers where id = ?";            BeanHandler
   
     handle = new BeanHandler<>(Customer.class);            Customer cust = runner.query(conn, sql, handle, 20);            System.out.println(cust);        } catch (Exception e) {            e.printStackTrace();        } finally {            JDBCUtils.closeResource(conn,null);        }    }

BeanListHandler：是ResultSetHandler接口的实现类，用于封装表中的多条记录构成的集合

public void testInsert2() {        Connection conn = null;        try {            conn = JDBCUtils.getConnection1();            QueryRunner runner = new QueryRunner();            String sql = "select id,name,email,birth from customers where id < ?";            BeanListHandler
   
     handle = new BeanListHandler<>(Customer.class);            List
    
      list = runner.query(conn, sql, handle, 20);            list.forEach(System.out::println);        } catch (Exception e) {            e.printStackTrace();        } finally {            JDBCUtils.closeResource(conn,null);        }    }

MapHandler：是ResultSetHandler接口的实现类，对应表中的一条记录，将字段及相应字段的值作为map中的key和value

public void testInsert3() {        Connection conn = null;        try {            conn = JDBCUtils.getConnection1();            QueryRunner runner = new QueryRunner();            String sql = "select id,name,email,birth from customers where id = ?";            MapHandler handler = new MapHandler();            Map
   
     map = runner.query(conn, sql, handler, 20);            System.out.println(map);        } catch (Exception e) {            e.printStackTrace();        } finally {            JDBCUtils.closeResource(conn,null);        }    }

MapListHandler：是ResultSetHandler接口的实现类，对应表中的多条记录，将字段及相应字段的值作为map中的key和value

public void testInsert4() {        Connection conn = null;        try {            conn = JDBCUtils.getConnection1();            QueryRunner runner = new QueryRunner();            String sql = "select id,name,email,birth from customers where id < ?";            MapListHandler handler = new MapListHandler();            List
    
     > list = runner.query(conn, sql, handler, 20);            list.forEach(System.out::println);        } catch (Exception e) {            e.printStackTrace();        } finally {            JDBCUtils.closeResource(conn,null);        }    }

用于查询特殊值，使用ScalarHandler

比如总数，平均数，最大数，最小数等

public void testquery() {        Connection conn = null;        try {            conn = JDBCUtils.getConnection1();            QueryRunner runner = new QueryRunner();            String sql = "select count(*) from customers ";            ScalarHandler handler = new ScalarHandler();            Long count = (Long) runner.query(conn, sql, handler);            System.out.println(count);        } catch (Exception e) {            e.printStackTrace();        } finally {            JDBCUtils.closeResource(conn,null);        }    }

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