JavaEE04-Spring的JdbcTemplate

目的

减少用JDBC编写访问数据库的程序中的重复代码.

连接数据库, 创建JdbcTemplate

以连接JDK自带的Java DB(Apache Derby)为例

public JdbcTemplate jdbcTemplate() {
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName("org.apache.derby.jdbc.ClientDriver");
    dataSource.setUrl("jdbc:derby://localhost:1527/sample");
    dataSource.setUsername("app");
    dataSource.setPassword("app");
    return new JdbcTemplate(dataSource);
}

访问数据库的DAO编写示例

package dao;

import java.util.List;
import model.User;
import org.springframework.jdbc.core.JdbcTemplate;

public class UserDao {

    private JdbcTemplate jdbcTemplate;

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

    public List<User> getAll() {
        List<User> users = this.jdbcTemplate.query("select * from person", (rs, rownum) -> {
            return new User(rs.getString("userID"), rs.getInt("age"));
        });
        return users;
    }

    public void createTable() {
        String sql = "CREATE TABLE person\n"
                + "(\n"
                + "userID varchar(255),\n"
                + "age int,\n"
                + "CONSTRAINT pk_userID PRIMARY KEY (userID)"
                + ")";
        this.jdbcTemplate.execute(sql);
    }

    public void add(User user){
        String sql = "INSERT INTO APP.PERSON (USERID, AGE) VALUES (?, ?)";
        this.jdbcTemplate.update(sql, user.getUserID(), user.getAge());
    }

    public static void main(String[] args) {
        JdbcTemplate jdbcTemplate1 = new conf.AppConfig().jdbcTemplate();
        UserDao userDao = new UserDao();
        userDao.setJdbcTemplate(jdbcTemplate1);
        //userDao.createTable();
        userDao.add(new User("用户03",27));
        List<User> all = userDao.getAll();
        all.stream().forEach(user -> System.out.println(user.getUserID() + " : " + user.getAge()));
    }
}

模型

package model;
public class User {
    private String userID;
    private int age;

    public User() {
    }

    public User(String userID, int age) {
        this.userID = userID;
        this.age = age;
    }

    public String getUserID() {
        return userID;
    }

    public void setUserID(String userID) {
        this.userID = userID;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" + "userID=" + userID + ", age=" + age + '}';
    }
}

数据库

app.person表的数据如下

运行结果

user00 : 19
用户01 : 22
用户03 : 27

结果说明, 增加一个用户, userDao.add(new User(“用户03”,27));
然后用 List all = userDao.getAll(); 查询出增加后的全部用户.