1.数据插入-Insert

一灰灰blogSpringBootDB系列JdbcTemplateJdbcTemplateDB约 2029 字大约 7 分钟

db操作可以说是java后端的必备技能了,实际项目中,直接使用JdbcTemplate的机会并不多,大多是mybatis,hibernate,jpa或者是jooq,然后前几天写一个项目,因为db操作非常简单,就直接使用JdbcTemplate,然而悲催的发现,对他的操作并没有预期中的那么顺畅,所以有必要好好的学一下JdbcTemplate的CURD;本文为第一篇,插入数据

I. 环境

1. 配置相关

使用SpringBoot进行db操作引入几个依赖,就可以愉快的玩耍了,这里的db使用mysql,对应的pom依赖如

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
</dependencies>

接着就是db的配置信息,下面是连接我本机的数据库配置

## DataSource
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/story?useUnicode=true&characterEncoding=UTF-8&useSSL=false
spring.datasource.driver-class-name= com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=

2. 测试db

创建一个测试db

CREATE TABLE `money` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL DEFAULT '' COMMENT '用户名',
  `money` int(26) NOT NULL DEFAULT '0' COMMENT '钱',
  `is_deleted` tinyint(1) NOT NULL DEFAULT '0',
  `create_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `update_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
  PRIMARY KEY (`id`),
  KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

II. 使用姿势

直接引入jdbcTemplate,注入即可,不需要其他的操作

@Autowired
private JdbcTemplate jdbcTemplate;

1. sql直接插入一条数据

直接写完整的插入sql,这种方式比较简单粗暴

private boolean insertBySql() {
    // 简单的sql执行
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES ('一灰灰blog', 100, 0);";
    return jdbcTemplate.update(sql) > 0;
}

2. 参数替换方式插入

这种插入方式中,sql使用占位符?,然后插入值通过参数传入即可

private boolean insertBySqlParams() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";
    return jdbcTemplate.update(sql, "一灰灰2", 200, 0) > 0;
}

3. 通过Statement方式插入

通过Statement可以指定参数类型,这种插入方式更加安全,有两种常见的方式,注意设置参数时,起始值为1,而不是通常说的0

private boolean insertByStatement() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";
    return jdbcTemplate.update(sql, new PreparedStatementSetter() {
        @Override
        public void setValues(PreparedStatement preparedStatement) throws SQLException {
            preparedStatement.setString(1, "一灰灰3");
            preparedStatement.setInt(2, 300);
            byte b = 0;
            preparedStatement.setByte(3, b);
        }
    }) > 0;
}

private boolean insertByStatement2() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";
    return jdbcTemplate.update(new PreparedStatementCreator() {
        @Override
        public PreparedStatement createPreparedStatement(Connection connection) throws SQLException {
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setString(1, "一灰灰4");
            preparedStatement.setInt(2, 400);
            byte b = 0;
            preparedStatement.setByte(3, b);
            return preparedStatement;
        }
    }) > 0;
}

4. 插入并返回主键id

这个属于比较常见的需求了,我希望获取插入数据的主键id,用于后续的业务使用; 这时就需要用KeyHolder

/**
 * 新增数据,并返回主键id
 *
 * @return
 */
private int insertAndReturnId() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";
    KeyHolder keyHolder = new GeneratedKeyHolder();
    jdbcTemplate.update(new PreparedStatementCreator() {
        @Override
        public PreparedStatement createPreparedStatement(Connection connection) throws SQLException {
            // 指定主键
            PreparedStatement preparedStatement = connection.prepareStatement(sql, new String[]{"id"});
            preparedStatement.setString(1, "一灰灰5");
            preparedStatement.setInt(2, 500);
            byte b = 0;
            preparedStatement.setByte(3, b);
            return preparedStatement;
        }
    }, keyHolder);
    return keyHolder.getKey().intValue();
}

看上面的实现,和前面差不多,但是有一行需要额外注意, 在获取Statement时,需要制定主键,否则会报错

// 指定主键
PreparedStatement preparedStatement = connection.prepareStatement(sql, new String[]{"id"});

5. 批量插入

基本插入看完之后,再看批量插入,会发现和前面的姿势没有太大的区别,无非是传入一个数组罢了,如下面的几种使用姿势

private void batchInsertBySql() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES " +
            "('Batch 一灰灰blog', 100, 0), ('Batch 一灰灰blog 2', 100, 0);";
    int[] ans = jdbcTemplate.batchUpdate(sql);
    System.out.println("batch insert by sql: " + JSON.toJSONString(ans));
}

private void batchInsertByParams() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";

    Object[] param1 = new Object[]{"Batch 一灰灰 3", 200, 0};
    Object[] param2 = new Object[]{"Batch 一灰灰 4", 200, 0};
    int[] ans = jdbcTemplate.batchUpdate(sql, Arrays.asList(param1, param2));
    System.out.println("batch insert by params: " + JSON.toJSONString(ans));
}

private void batchInsertByStatement() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";

    int[] ans = jdbcTemplate.batchUpdate(sql, new BatchPreparedStatementSetter() {
        @Override
        public void setValues(PreparedStatement preparedStatement, int i) throws SQLException {
            if (i == 0) {
                preparedStatement.setString(1, "batch 一灰灰5");
            } else {
                preparedStatement.setString(1, "batch 一灰灰6");
            }
            preparedStatement.setInt(2, 300);
            byte b = 0;
            preparedStatement.setByte(3, b);
        }

        @Override
        public int getBatchSize() {
            return 2;
        }
    });
    System.out.println("batch insert by statement: " + JSON.toJSONString(ans));
}

6. 测试

接下来我们测试下上面的代码执行情况

@Component
public class InsertService {
    /**
     * 简单的新增一条数据
     */
    public void basicInsert() {
        System.out.println("basic insert: " + insertBySql());
        System.out.println("insertBySqlParams: " + insertBySqlParams());
        System.out.println("insertByStatement: " + insertByStatement());
        System.out.println("insertByStatement2: " + insertByStatement2());
        System.out.println("insertAndReturn: " + insertAndReturnId());

        List<Map<String, Object>> result = jdbcTemplate.queryForList("select * from money");
        System.out.println("after insert, the records:\n" + result);
    }
    
    /**
     * 批量插入数据
     */
    public void batchInsert() {
        batchInsertBySql();
        batchInsertByParams();
        batchInsertByStatement();
    }
}

@SpringBootApplication
public class Application {

    public Application(InsertService insertService) {
        insertService.basicInsert();
        insertService.batchInsert();
    }

    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }
}

输出结果如

basic insert: true
insertBySqlParams: true
insertByStatement: true
insertByStatement2: true
insertAndReturn: 5
after insert, the records:
[{id=1, name=一灰灰blog, money=100, is_deleted=false, create_at=2019-04-08 10:22:50.0, update_at=2019-04-08 10:22:50.0}, {id=2, name=一灰灰2, money=200, is_deleted=false, create_at=2019-04-08 10:22:55.0, update_at=2019-04-08 10:22:55.0}, {id=3, name=一灰灰3, money=300, is_deleted=false, create_at=2019-04-08 10:22:55.0, update_at=2019-04-08 10:22:55.0}, {id=4, name=一灰灰4, money=400, is_deleted=false, create_at=2019-04-08 10:22:55.0, update_at=2019-04-08 10:22:55.0}, {id=5, name=一灰灰5, money=500, is_deleted=false, create_at=2019-04-08 10:22:55.0, update_at=2019-04-08 10:22:55.0}]
batch insert by sql: [2]
batch insert by params: [1,1]
batch insert by statement: [1,1]
执行结果
执行结果

II. 扩展

1. 批量插入并返回主键id

上面还漏了一个批量插入时,也需要返回主键id,改怎么办?

直接看JdbcTemplate的接口,并没有发现类似单个插入获取主键的方式,是不是意味着没法实现呢?

当然不是了,既然没有提供,我们完全可以依葫芦画瓢,自己实现一个 ExtendJdbcTemplate, 首先看先单个插入返回id的实现如

源码
源码

接下来,我们自己的实现可以如下

public class ExtendJdbcTemplate extends JdbcTemplate {
    public ExtendJdbcTemplate(DataSource dataSource) {
        super(dataSource);
    }

    public int[] batchUpdate(final String sql, final BatchPreparedStatementSetter pss,
            final KeyHolder generatedKeyHolder) throws DataAccessException {
        return execute(new PreparedStatementCreator() {
            @Override
            public PreparedStatement createPreparedStatement(Connection conn) throws SQLException {
                return conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
            }
        }, ps -> {
            try {
                int batchSize = pss.getBatchSize();
                int totalRowsAffected = 0;
                int[] rowsAffected = new int[batchSize];
                List generatedKeys = generatedKeyHolder.getKeyList();
                generatedKeys.clear();
                ResultSet keys = null;
                for (int i = 0; i < batchSize; i++) {
                    pss.setValues(ps, i);
                    rowsAffected[i] = ps.executeUpdate();
                    totalRowsAffected += rowsAffected[i];
                    try {
                        keys = ps.getGeneratedKeys();
                        if (keys != null) {
                            RowMapper rowMapper = new ColumnMapRowMapper();
                            RowMapperResultSetExtractor rse = new RowMapperResultSetExtractor(rowMapper, 1);
                            generatedKeys.addAll(rse.extractData(keys));
                        }
                    } finally {
                        JdbcUtils.closeResultSet(keys);
                    }
                }
                if (logger.isDebugEnabled()) {
                    logger.debug("SQL batch update affected " + totalRowsAffected + " rows and returned " +
                            generatedKeys.size() + " keys");
                }
                return rowsAffected;
            } finally {
                if (pss instanceof ParameterDisposer) {
                    ((ParameterDisposer) pss).cleanupParameters();
                }
            }
        });
    }
}

封装完毕之后,我们的使用姿势可以为

@Autowired
private ExtendJdbcTemplate extendJdbcTemplate;

private void batchInsertAndReturnId() {
    String sql = "INSERT INTO `money` (`name`, `money`, `is_deleted`) VALUES (?, ?, ?);";

    GeneratedKeyHolder generatedKeyHolder = new GeneratedKeyHolder();
    extendJdbcTemplate.batchUpdate(sql, new BatchPreparedStatementSetter() {
        @Override
        public void setValues(PreparedStatement preparedStatement, int i) throws SQLException {
            if (i == 0) {
                preparedStatement.setString(1, "batch 一灰灰7");
            } else {
                preparedStatement.setString(1, "batch 一灰灰8");
            }
            preparedStatement.setInt(2, 400);
            byte b = 0;
            preparedStatement.setByte(3, b);
        }

        @Override
        public int getBatchSize() {
            return 2;
        }
    }, generatedKeyHolder);

    System.out.println("batch insert and return id ");
    List<Map<String, Object>> objectMap = generatedKeyHolder.getKeyList();
    for (Map<String, Object> map : objectMap) {
        System.out.println(map.get("GENERATED_KEY"));
    }
}

然后测试执行,输出结果如下

批量插入返回id
批量插入返回id

2. 小结

本篇主要介绍使用JdbcTemplate插入数据的几种常用姿势,分别从单个插入和批量插入进行了实例演示,包括以下几种常见姿势

  • update(sql)
  • update(sql, param1, param2...)
  • update(sql, new PreparedStatementCreator(){})
  • update(new PreparedStatementSetter(){})
  • update(new PreparedStatementCreator(){}, new GeneratedKeyHolder())

批量插入姿势和上面差不多,唯一需要注意的是,如果你想使用批量插入,并获取主键id,目前我没有找到可以直接使用的接口,如果有这方面的需求,可以参考下我上面的使用姿势

IV. 其他

0. 项目

Loading...