Spring- JdbcTemplate(CRUD)

1.1 Project directory

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1.2 Code example

Account entity class

package cn.guardwhy.domain;
/**
 * 账户实体类
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Account {
    
    
    private Integer id;
    private String name;
    private Float money;
}

Test code

package cn.guardwhy.jdbc;

import cn.guardwhy.domain.Account;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

/**
 * spring JdbcTemplate实现完整CRUD操作
 */
public class JdbcTemplateCRUD {
    
    
    public static void main(String[] args) {
    
    
        // 1.加载spring配置文件,创建spring IOC容器
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:bean.xml");
        // 2.从spring IOC容器中,获取JdbcTemplate
        JdbcTemplate jdbcTemplate = (JdbcTemplate) context.getBean("jdbcTemplate");
        // 3.查询多行
        List<Account> list = jdbcTemplate.query("select id,name,money from account", new RowMapper<Account>() {
    
    
            @Override
            public Account mapRow(ResultSet rs, int index) throws SQLException {
    
    
                // 创建账户对象
                Account account = new Account();
                account.setId(rs.getInt("id"));
                account.setName(rs.getString("name"));
                account.setMoney(rs.getFloat("money"));
                return account;
            }
        });
        // 4.打印结果集
        for(Account account:list){
    
    
            System.out.println(account);
        }
        // 5.查询一行一列
        System.out.println("查询一行一列-------");
        Integer accountNum = jdbcTemplate.queryForObject("select count(*) from account", Integer.class);
        System.out.println("当前账户数量:" + accountNum);
    }
}

Results of the

1.3 Custom RowMapper

package cn.guardwhy.resources;

import cn.guardwhy.domain.Account;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;


public class AccountRowMapper implements RowMapper<Account> {
    
    
    /**
     * 结果集映射的方法：
     *      结果集中的每一行记录，都会调用一次该方法
     */
    public Account mapRow(ResultSet rs, int index) throws SQLException{
    
    
        // 创建账户对象
        Account account = new Account();
        account.setId(rs.getInt("id"));
        account.setName(rs.getString("name"));
        account.setMoney(rs.getFloat("money"));
        return account;
    }
}

1.4 Test code

package cn.guardwhy.jdbc;

import cn.guardwhy.domain.Account;
import cn.guardwhy.resources.AccountRowMapper;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import java.util.List;

/**
 * spring JdbcTemplate实现完整CRUD操作
 */
public class JdbcTemplateCRUD {
    
    
    public static void main(String[] args) {
    
    
        // 1.加载spring配置文件,创建spring IOC容器
        ApplicationContext context = new ClassPathXmlApplicationContext("classpath:bean.xml");
        // 2.从spring IOC容器中,获取JdbcTemplate
        JdbcTemplate jdbcTemplate = (JdbcTemplate) context.getBean("jdbcTemplate");
        // 3.使用自定义的RowMapper
        List<Account> list = jdbcTemplate.query("select * from account", new AccountRowMapper());

        // 4.打印结果集
        for(Account account:list){
    
    
            System.out.println(account);
        }
        // 5.查询一行一列
        System.out.println("查询一行一列-------");
        Integer accountNum = jdbcTemplate.queryForObject("select count(*) from account", Integer.class);
        System.out.println("当前账户数量:" + accountNum);
    }
}

1.5 Execution results

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