Java Spring-JdbcTemplate增删改查

Posted 2020-10-14 hyserendipity

2017-11-11 21:13:13

Spring 框架中提供了对持久层技术支持的类 :

• JDBC : org.springframework.jdbc.core.support.JdbcDaoSupport
• Hibernate 3.0 : org.springframework.orm.hibernate3.support.HibernateDaoSupport
• iBatis : org.springframework.orm.ibatis.support.SqlMapClientDaoSupport

增加，删除和修改的操作还是比较容易的，因为，并不需要有返回值。

增加，删除和修改的代码：

// User
public class User {
    private Integer id;
    private String name;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name=‘" + name + ‘\‘‘ +
                ‘}‘;
    }
}

// UserDao
public class UserDao extends JdbcDaoSupport {

    public void add(User user){
        String sql = "insert into user values(?,?)";
        getJdbcTemplate().update(sql,user.getId(),user.getName());
    }

    public void delete(User user){
        String sql = "delete from user where id=?";
        getJdbcTemplate().update(sql, user.getId());
    }

    public void update(User user){
        String sql = "update user set name=? where id=?";
        getJdbcTemplate().update(sql, user.getName(), user.getId());
    }

}

// 测试
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:config4.xml")
public class Jdbc3 {

    @Resource(name = "userdao")
    private UserDao userdao;

    @Test
    public void demo(){
        User user= new User();
        user.setName("刘亦菲");
        user.setId(001);

        // userdao.add(user);

        //user.setName("胡歌");
        //userdao.update(user);

        userdao.delete(user);
    }
}

查找操作是相对比较麻烦的，因为这里一般是有返回值的。

针对返回值为基本类型的，可以比较方便的进行转换；

针对返回值是对象的，需要自定义转换方法；

查询代码：

// UserDao
public class UserDao extends JdbcDaoSupport {

    public void add(User user){
        String sql = "insert into user values(?,?)";
        getJdbcTemplate().update(sql,user.getId(),user.getName());
    }

    public void delete(User user){
        String sql = "delete from user where id=?";
        getJdbcTemplate().update(sql, user.getId());
    }

    public void update(User user){
        String sql = "update user set name=? where id=?";
        getJdbcTemplate().update(sql, user.getName(), user.getId());
    }

    public int findCount(){
        String sql = "select count(*) from user";
        return this.getJdbcTemplate().queryForObject(sql,Integer.class);
    }

    public String findNameByID(int id){
        String sql = "select name from user where id = ?";
        return getJdbcTemplate().queryForObject(sql,String.class,id);
    }

    public User findUserByID(int id){
        String sql = "select * from user where id = ?";
        return getJdbcTemplate().queryForObject(sql, new MyRowMap(), id);
    }

    public List<User> findAll(){
        String sql = "select * from user";
        return getJdbcTemplate().query(sql,new MyRowMap());
    }

    // 匿名内部类进行自定义的类型转换
    class MyRowMap implements RowMapper<User>{

        /**
         *
         * @param resultSet:结果集，里面包含所有的结果
         * @param i：行号
         * @return 将每一行的数据自行转成需要的对象的数据类型
         * @throws SQLException
         */
        @Override
        public User mapRow(ResultSet resultSet, int i) throws SQLException {
            User user = new User();
            user.setName(resultSet.getString("name"));
            user.setId(resultSet.getInt("id"));
            return user;
        }
    }
}

// 查询
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:config4.xml")
public class Jdbc3 {

    @Resource(name = "userdao")
    private UserDao userdao;

    @Test
    public void demo(){
        User user= new User();
        user.setName("章子怡");
        user.setId(002);

        userdao.add(user);
    }

    @Test
    public void demo2(){
        System.out.println(userdao.findCount());

        List<User> ls = userdao.findAll();
        for(User user:ls){
            System.out.println(user);
        }
    }
}