我使用的是spring 4.0（boot），代码如下：
String sql = "SELECT emp_id,name,role FROM employees";
List<Employee> employees = jdbcTemplate.query(sql,(rs, rowNum)->
new Employee(rs.getInt("emp_id"), rs.getString("name"),
rs.getString("role")));
employees.forEach(employee -> {log.info(employee.toString());
log.info("part a");});代码看起来简单明了，但问题是员工根本不返回日志中的任何内容。这不意味着雇员中的所有内容都是空的吗？
记录器本身应该没有问题，因为在这段代码工作之前，日志记录就已经完成了。
数据库输入正确。当我通过mysql客户端进行查询时，我可以在那里看到它们。
我犯了什么样的java错误（如果是这样的话）？
编辑：这是我执行简单数据库查询的全部功能，上面的代码来自于此：
@Override
public void run(String... args) throws Exception {
log.info("Creating tables");
jdbcTemplate.execute("DROP TABLE IF EXISTS employee");
jdbcTemplate.execute("CREATE TABLE employee (emp_id int, name varchar(100), role varchar(100))");
log.info("Inserting Baggins Hopkins");
int rowsAffected = jdbcTemplate.update("INSERT INTO EMPLOYEE(EMP_ID, NAME, ROLE)"
+ " VALUES(1,'Baggins Hopkins','thief')");
log.info("rows affected: "+ Integer.toString(rowsAffected));
int rowsAffected1 = jdbcTemplate.update("INSERT INTO EMPLOYEE(EMP_ID, NAME, ROLE)"
+ " VALUES(2,'Doolous Hopkins','robber')");
log.info("rows affected: "+ Integer.toString(rowsAffected1));
log.info("Querying for employee");
String sql = "SELECT emp_id,name,role FROM employee";
List<Employee> employees = jdbcTemplate.query(sql,(rs, rowNum)->
new Employee(rs.getInt("emp_id"), rs.getString("name"),
rs.getString("role")));
log.info("Part A:");
log.info(String.valueOf(employees.isEmpty()));
// List<Employee> employees = new ArrayList<Employee>();
// final List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);
// for(final Map row : rows) {
// Employee employee = new Employee();
// employee.setId((int)row.get("emp_id"));
// employee.setName((String)row.get("name"));
// employee.setRole((String)row.get("role"));
// };
employees.forEach(employee -> {log.info(employee.toString());
log.info("part a");});
}这是发生错误时的日志：
:: Spring Boot :: (v2.1.0.RELEASE)
2018-11-07 22:08:36.599 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : Starting JdbcTest1Application on KitKat with PID 5476 (C:\Users\Nano\Downloads\jdbc-test1\jdbc-test1\target\classes started by Nano in C:\Users\Nano\Downloads\jdbc-test1\jdbc-test1)
2018-11-07 22:08:36.599 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : No active profile set, falling back to default profiles: default
2018-11-07 22:08:37.458 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : Started JdbcTest1Application in 1.156 seconds (JVM running for 2.08)
2018-11-07 22:08:37.474 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : Creating tables
2018-11-07 22:08:37.474 INFO 5476 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2018-11-07 22:08:37.614 INFO 5476 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2018-11-07 22:08:38.873 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : Inserting Baggins Hopkins
2018-11-07 22:08:39.042 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : rows affected: 1
2018-11-07 22:08:39.183 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : rows affected: 1
2018-11-07 22:08:39.183 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : Querying for employee
2018-11-07 22:08:39.214 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : Part A:
2018-11-07 22:08:39.214 INFO 5476 --- [ main] c.j.jdbctest1.JdbcTest1Application : true
2018-11-07 22:08:39.230 INFO 5476 --- [ Thread-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown initiated...
2018-11-07 22:08:39.230 INFO 5476 --- [ Thread-1] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown completed.
2条答案
按热度按时间hrysbysz1#
您可以使用其他方式获取员工列表：
或
0yycz8jy2#
原版海报回答：
这是一个简单的语法错误。正如评论员指出的那样，我一直插错了表格。。。我的sql查询语法错误。
以前，我是在“employees”中插入，但我应该在“employees”中插入
但是，返回包含map的列表的queryforlist（）仍然返回null。我在上面的帖子中对此进行了评论。我不知道这有什么问题（我以前没有尝试过使用list>）。但问题解决了。