spring jdbcTemplate配置

1. 创建Account类和AccountDao接口

public class Account {
    private long id;
    private String ownerName;
    private double balance;
    private Date accessTime;
    private boolean locked;
    ...

public interface AccountDao {
    public void insert(Account account);
    public void update(Account account);
    public void update(List<Account> accounts);
    public void delete(long accountId);
    public Account find(long accountId);
    public List<Account> find(List<Long> accountIds);
    public List<Account> find(String ownerName);
    public List<Account> find(boolean locked);
}

2. 实现AccountDao接口的AccountDaoJdbcImpl类

public class AccountDaoJdbcImpl implements AccountDao {

	private JdbcTemplate jdbcTemplate;

	public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
		this.jdbcTemplate = jdbcTemplate;
	}

	public void insert(Account account) {
		// TODO Auto-generated method stub

	}

3. 使用jdbcTemplate类定义jdbcTemplate Bean,并使用dataSource Bean 满足DataSource其依赖

@Bean
public DataSource dataSource() {
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName("org.h2.Driver");
    dataSource.setUrl("jdbc:h2:tcp://localhost/~/test");
    dataSource.setUsername("sa");
    dataSource.setPassword("");
    return dataSource;
}

@Bean
public JdbcTemplate jdbcTemplate() {
    JdbcTemplate jdbcTemplate = new JdbcTemplate();
    jdbcTemplate.setDataSource(dataSource());
    return jdbcTemplate;
}

4. 使用AccountDaoJdbcImpl创建accountDao bean,并将jdbcTemplate Bean注入其中:

@Bean
public AccountDao accountDao() {
    AccountDaoJdbcImpl accountDao = new AccountDaoJdbcImpl();
    accountDao.setJdbcTemplate(jdbcTemplate());
    return accountDao;
}

5. main中查找accountDao bean

AccountDao accountDao = applicationContext.getBean(AccountDao.class);

之后便意味着可以在accountdaojdbcimpl中使用jdbctemplate 了。

6. 使用jdbctemplate运行查询

public Account find(long accountId) {
	return jdbcTemplate
			.queryForObject(
					"select id,owner_name,balance,access_time,locked from account where id = ?",
					new RowMapper<Account>() {
						public Account mapRow(ResultSet rs, int rowNum)
								throws SQLException {
							Account account = new Account();
							account.setId(rs.getLong("id"));
							account.setOwnerName(rs.getString("owner_name"));
							account.setBalance(rs.getDouble("balance"));
							account.setAccessTime(rs
									.getTimestamp("access_time"));
							account.setLocked(rs.getBoolean("locked"));
							return account;
						}

					}, accountId);
}

使用jdbctemplate的 queryforobject方法。

调用参数是

public <T> T queryForObject(String sql, RowMapper<T> rowMapper, Object... args) throws DataAccessException {
     List<T> results = (List)this.query((String)sql, (Object[])args, (ResultSetExtractor)(new RowMapperResultSetExtractor(rowMapper, 1)));
     return DataAccessUtils.requiredSingleResult(results);
 }

第一个参数是string的sql 语句，sql语句里面用问号做了占位符。第二个是RowMapper的接口，这里创建了一个匿名类，第三个之后是可变参数列表。

public interface RowMapper<T> {
    T mapRow(ResultSet var1, int var2) throws SQLException;
}

RowMapper 里面就一个函数，mapRow,从ResultSet对象中获取值填充属性。比如这里的，new了一个Account对象，然后把ResultSet里面的属性填充一下就行了。

在main中这样调用即可:

AccountDao accountDao = applicationContext.getBean(AccountDao.class);
Account account = accountDao.find(100L);