Spring SimpleJdbcTemplate查询示例

这里有几个例子来说明如何使用SimpleJdbcTemplate query()方法来查询或从数据库中提取数据。在 JdbcTemplate query() 方法，需要手动转换返回的结果转换为一个目标对象类型，并传递一个对象数组作为参数。在SimpleJdbcTemplate类，它是更加人性化和简单。jdbctemplate VS simplejdbctemplate
请比较JdbcTemplate类的示例和SimpleJdbcTemplate类的示例。1.查询单行这里有向你展示了如何查询或从数据库中提取单行的两种方式，并将其转换成一个模型类。

1.1 自定义RowMapper

在一般情况下，它总是建议来实现 RowMapper 接口来创建自定义的RowMapper，以满足您的需求。

package com.yiibai.customer.model;import java.sql.ResultSet;
import java.sql.SQLException;import org.springframework.jdbc.core.RowMapper;public class CustomerRowMapper implements RowMapper
{
public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
Customer customer = new Customer();
customer.setCustId(rs.getInt("CUST_ID"));
customer.setName(rs.getString("NAME"));
customer.setAge(rs.getInt("AGE"));
return customer;
}}

public Customer findByCustomerId(int custId){String sql = "SELECT * FROM CUSTOMER WHERE CUST_ID = ?";Customer customer = getSimpleJdbcTemplate().queryForObject(
sql,  new CustomerParameterizedRowMapper(), custId);return customer;
}

1.2 BeanPropertyRowMapper

在SimpleJdbcTemplate类，需要使用“ParameterizedBeanPropertyRowMapper’ 代替 ‘BeanPropertyRowMapper”。

public Customer findByCustomerId2(int custId){String sql = "SELECT * FROM CUSTOMER WHERE CUST_ID = ?";Customer customer = getSimpleJdbcTemplate().queryForObject(sql,
          ParameterizedBeanPropertyRowMapper.newInstance(Customer.class), custId);return customer;
}

2，查询多行从数据库查询或提取多行记录，并将其转换成一个列表。

2.1 ParameterizedBeanPropertyRowMapper

public List<Customer> findAll(){String sql = "SELECT * FROM CUSTOMER";List<Customer> customers =
getSimpleJdbcTemplate().query(sql,
   ParameterizedBeanPropertyRowMapper.newInstance(Customer.class));return customers;
}

3.查询单值查询或提取数据库中的单个列的值。3.1单列名它显示了如何查询单个列名作为字符串。

public String findCustomerNameById(int custId){String sql = "SELECT NAME FROM CUSTOMER WHERE CUST_ID = ?";String name = getSimpleJdbcTemplate().queryForObject(
sql, String.class, custId);return name;}

3.2、行总数它展示了如何从数据库中查询行的总数。

public int findTotalCustomer(){String sql = "SELECT COUNT(*) FROM CUSTOMER";int total = getSimpleJdbcTemplate().queryForInt(sql);return total;
}

运行它

package com.yiibai.common;import java.util.ArrayList;
import java.util.List;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yiibai.customer.dao.CustomerDAO;
import com.yiibai.customer.model.Customer;public class SimpleJdbcTemplateApp
{
    public static void main( String[] args )
    {
     ApplicationContext context =
    new ClassPathXmlApplicationContext("Spring-Customer.xml");         CustomerDAO customerSimpleDAO =
                (CustomerDAO) context.getBean("customerSimpleDAO");         Customer customerA = customerSimpleDAO.findByCustomerId(1);
         System.out.println("Customer A : " + customerA);         Customer customerB = customerSimpleDAO.findByCustomerId2(1);
         System.out.println("Customer B : " + customerB);         List<Customer> customerAs = customerSimpleDAO.findAll();
         for(Customer cust: customerAs){
          System.out.println("Customer As : " + customerAs);
         }         List<Customer> customerBs = customerSimpleDAO.findAll2();
         for(Customer cust: customerBs){
          System.out.println("Customer Bs : " + customerBs);
         }         String customerName = customerSimpleDAO.findCustomerNameById(1);
         System.out.println("Customer Name : " + customerName);         int total = customerSimpleDAO.findTotalCustomer();
         System.out.println("Total : " + total);    }
}

总结

SimpleJdbcTemplate 是不能代替 JdbcTemplate 的，它只是一个Java5的友好补充它。下载代码 – http://pan.baidu.com/s/1eRisz6M