JDBC练习-查询所有

1.获取connection对象

先导入需要的jar包:mysql-connector-java;druid-jar

Properties pop = new Properties();
pop.load(new FileInputStream("src/druid.properties"));
DataSource dataSource = DruidDataSourceFactory.createDataSource(pop);
Connection connection = dataSource.getConnection();

2.定义SQL语句

String sql = "select * from tb_brand";

3.获取PreparedStatement对象

PreparedStatement pstas = connection.prepareStatement(sql);

4.设置参数

5.执行sql

ResultSet rs = pstas.executeQuery();

6.处理结果

Brand brand = null;
List<Brand> brands = new ArrayList<>();
while (rs.next()) {
    int id = rs.getInt("id");
    String brandName = rs.getString("brand_name");
    String companyName = rs.getString("company_name");
    int ordered = rs.getInt("ordered");
    String description = rs.getString("description");
    int status = rs.getInt("status");
    brand = new Brand();
    brand.setId(id);
    brand.setBrandName(brandName);
    brand.setCompanyName(companyName);
    brand.setOrdered(ordered);
    brand.setDescription(description);
    brand.setStatus(status);
    brands.add(brand);
}
System.out.println(brands);

7.释放资源

rs.close();
connection.close();
pstas.close();