JDBC编程-优化程序（六）

首先完成DTO类的编写

DTO类是data tranfer object也就是数据传输类，DTO主要用于数据的传输操作，其中包含属性值，以及构造方法和getter ，setter方法等，不会包含业务逻辑。 
首先是Identity类，这个是抽象类。

public abstract class IdEntity {    protected long id;    public long getId() {        return id;    }    public void setId(long id) {        this.id = id;    }}
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Address和User类分别对应数据库中的表格tbl_user和tbl_address. 
代码如下：

public class User extends IdEntity {    private String name;    private String password;    private String email;    public User(String name, String password, String email) {        this.name = name;        this.password = password;        this.email = email;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public String getEmail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }    @Override    public String toString() {        return "User [name=" + name + ", password=" + password + ", email="                + email + ", id=" + id + "]";    }}
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Address类的代码：

public class Address extends IdEntity {    private String city;    private String country;    private String userid;    public String getCity() {        return city;    }    public void setCity(String city) {        this.city = city;    }    public String getCountry() {        return country;    }    public void setCountry(String country) {        this.country = country;    }    public String getUserid() {        return userid;    }    public void setUserid(String userid) {        this.userid = userid;    }    @Override    public String toString() {        return "Address [city=" + city + ", country=" + country + ", userid="                + userid + ", id=" + id + "]";    }}
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DAO类的实现

DAO 是data access object即是数据访问对象的缩写。 
使用了PreparedStatement这个类，这个类可以使用占位符，然后使用方法再来设置参数。 
最后execute执行。 
具体代码如下： 
首先定了借口UserDao

public interface UserDao {    public void save(Connection conn,User user) throws SQLException;    public void update(Connection conn,Long id,User user)throws SQLException;    public void delete(Connection conn,User user) throws SQLException;}
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具体实现类代码：

public void save(Connection conn, User user) throws SQLException {        // TODO Auto-generated method stub        PreparedStatement ps = conn.prepareCall("INSERT INTO tbl_user(name,password,email) VALUES (?,?,?)");        ps.setString(1, user.getName());        ps.setString(2, user.getPassword());        ps.setString(3, user.getEmail());        ps.execute();    }    @Override    public void update(Connection conn, Long id, User user) throws SQLException {        // TODO Auto-generated method stub        String sql = "UPDATE tbl_user SET name=?,password=?,email=? WHERE id=?";        PreparedStatement ps = conn.prepareStatement(sql);        ps.setString(1, user.getName());        ps.setString(2, user.getPassword());        ps.setString(3, user.getEmail());        ps.setLong(4, id);        ps.execute();    }    @Override    public void delete(Connection conn, User user) throws SQLException {        // TODO Auto-generated method stub        PreparedStatement ps = conn.prepareStatement("DELETE FROM tbl_user WHERE id=?");        ps.setLong(1, user.getId());        ps.execute();    }}
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写了一个一个测试类往tbl_user里面插入一行数据。 
具体代码如下：

public class DaoTest {    /**     * @param args     */    public static void main(String[] args) {        Connection conn = null;        try {            conn = ConnectionFactory.getInstance().makeConnection();            conn.setAutoCommit(false);            UserDao userDao = new UserDaoImpl();            User tom = new User("Tom", "123456", "[e-mail]");            userDao.save(conn, tom);            conn.commit();        } catch (Exception e) {            e.printStackTrace();            try {                conn.rollback();            } catch (Exception e2) {                e2.printStackTrace();            }        }    }}