JDBC JdbTemplate&NamedParameterJdbcTemplate（Spring工具类）

使用该工具类需要从spring开发包中导入spring.jar和commons-logging.jar，这个模板是线程安全的。

 

JdbcTemplate:

public class JdbcTemplateTest {

    static JdbcTemplate jdbc = new JdbcTemplate(JdbcUtils.getDataSource());

    /**
     * @param args
     */
    public static void main(String[] args) {
        User user = findUser("zhangsan");
        // System.out.println("user:" + user);

        // System.out.println("users:" + findUsers(3));

        // System.out.println("user count:" + getUserCount());

        // System.out.println("user name:" + getUserName(1));

        System.out.println("data:" + getData(1));
    }

    static int addUser(final User user) {
        jdbc.execute(new ConnectionCallback() {//想在插入的时候取主键，回调

            public Object doInConnection(Connection con) throws SQLException, DataAccessException {
                String sql = "insert into user(name,birthday, money) values (?,?,?) ";
                PreparedStatement ps = con.prepareStatement(sql,
                        Statement.RETURN_GENERATED_KEYS);
                ps.setString(1, user.getName());
                ps.setDate(2, new java.sql.Date(user.getBirthday().getTime()));
                ps.setFloat(3, user.getMoney());
                ps.executeUpdate();

                ResultSet rs = ps.getGeneratedKeys();
                if (rs.next())
                    user.setId(rs.getInt(1));
                return null;
            }
        });
        return 0;
    }

    static Map getData(int id) {
        String sql = "select id as userId, name, money, birthday  from user where id="
                + id;
        return jdbc.queryForMap(sql);
    }

    static String getUserName(int id) {
        String sql = "select name from user where id=" + id;
        Object name = jdbc.queryForObject(sql, String.class);
        return (String) name;
    }

    static int getUserCount() {
        String sql = "select count(*) from user";
        return jdbc.queryForInt(sql);//直接把结果返回成int型，也可以查询最大值平均值之类的
    }

    static List findUsers(int id) {
        String sql = "select id, name, money, birthday  from user where id<?";
        Object[] args = new Object[] { id };
        int[] argTypes = new int[] { Types.INTEGER };
        List users = jdbc.query(sql, args, argTypes, new BeanPropertyRowMapper(
                User.class));//查询结果是多条记录
        return users;
    }

    static User findUser(String name) {
        String sql = "select id, name, money, birthday  from user where name=?";
        Object[] args = new Object[] { name };
        Object user = jdbc.queryForObject(sql, args, new BeanPropertyRowMapper(
                User.class));//queryForObject查询如果查不到数据或者多于一条数据会报错
        return (User) user;
    }

    static User findUser1(String name) {
        String sql = "select id, name, money, birthday  from user where name=?";
        Object[] args = new Object[] { name };
        Object user = jdbc.queryForObject(sql, args, new RowMapper() {

            public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
                User user = new User();
                user.setId(rs.getInt("id"));
                user.setName(rs.getString("name"));
                user.setMoney(rs.getFloat("money"));
                user.setBirthday(rs.getDate("birthday"));
                return user;
            }
        });
        return (User) user;
    }
}

 

 

 

NamedParameterJdbcTemplate :包含JdbcTemplate的功能，特点是可以解析sql语句中的非？参数，而且可以直接用sql去匹配bean中的属性。

public class NamedJdbcTemplate {
    static NamedParameterJdbcTemplate named = new NamedParameterJdbcTemplate(
            JdbcUtils.getDataSource());

    /**
     * @param args
     */
    public static void main(String[] args) {
        User user = new User();
        user.setMoney(10);
        user.setId(2);
        System.out.println(findUser1(user));
    }

    static void addUser(User user) {
        String sql = "insert into user(name,birthday, money) values (:name,:birthday,:money) ";
        SqlParameterSource ps = new BeanPropertySqlParameterSource(user); //使用bean来设置sql中的参数
        KeyHolder keyHolder = new GeneratedKeyHolder(); 
        named.update(sql, ps, keyHolder); //获取主键
        int id = keyHolder.getKey().intValue();
        user.setId(id);
       
        Map map = keyHolder.getKeys(); //如果主键是多个，可以用该方法获取成Map映射
    }

    static User findUser(User user) {
        String sql = "select id, name, money, birthday  from user "
                + "where money > :m and id < :id";
        Map params = new HashMap();
        // params.put("n", user.getName());
        params.put("m", user.getMoney());
        params.put("id", user.getId()); //使用Map来设置sql的参数
        Object u = named.queryForObject(sql, params, new BeanPropertyRowMapper(
                User.class)); //第三个参数是一个映射器，将获取的数据映射给Bean
        return (User) u;
    }

    static User findUser1(User user) {
        String sql = "select id, name, money, birthday  from user "
                + "where money > :money and id < :id";
        SqlParameterSource ps = new BeanPropertySqlParameterSource(user);
        Object u = named.queryForObject(sql, ps, new BeanPropertyRowMapper(
                User.class));
        return (User) u;
    }

}

 

 

 

 

SimpleJdbcTemplate：在前两者基础上支持了可变参数和泛型

public class SimpleJdbcTemplateTest {
    static SimpleJdbcTemplate simple = new SimpleJdbcTemplate(JdbcUtils
            .getDataSource());

    static User find(String name) {
        String sql = "select id, name, money, birthday  from user where name=? and money > ?";
        User user = simple.queryForObject(sql,
                ParameterizedBeanPropertyRowMapper.newInstance(User.class),
                name, 100f);
        return user;
       
        //simple.getNamedParameterJdbcOperations().update(sql,paramSource,keyHolder);先获取NamedJdbcTemplate模板，再获取主键
        //simple.getJdbcOperations()获取JdbcTemplate
    }

}

 

 

 

上面代码引用的自定义工具类的代码：

public final class JdbcUtils {
    private static String url = "jdbc:mysql://localhost:3306/jdbc";
    private static String user = "root";
    private static String password = "";
    private static DataSource myDataSource = null;

    private JdbcUtils() {
    }

    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            // myDataSource = new MyDataSource2();
            Properties prop = new Properties();
            // prop.setProperty("driverClassName", "com.mysql.jdbc.Driver");
            // prop.setProperty("user", "user");

            InputStream is = JdbcUtils.class.getClassLoader()
                    .getResourceAsStream("dbcpconfig.properties");
            prop.load(is);
            myDataSource = BasicDataSourceFactory.createDataSource(prop);
        } catch (Exception e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    public static DataSource getDataSource() {
        return myDataSource;
    }

    public static Connection getConnection() throws SQLException {
        // return DriverManager.getConnection(url, user, password);
        return myDataSource.getConnection();
    }

    public static void free(ResultSet rs, Statement st, Connection conn) {
        try {
            if (rs != null)
                rs.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (st != null)
                    st.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally {
                if (conn != null)
                    try {
                        conn.close();
                        // myDataSource.free(conn);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
            }
        }
    }
}