今天完成的事情：

今天主要是用jdbc默认的连接池使用jdbcTemplate对数据库进行增删改查

代码如下

首先配置applicationContext.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <!--配置默认连接池-->
    <context:property-placeholder location="db.properties"/>
     <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
         <property name="driverClassName" value="${driverClass}"/>
         <property name="url" value="${jdbcUrl}"/>
         <property name="username" value="${user}"/>
         <property name="password" value="${password}"/>
     </bean>

    <!--定义jdbcTemplate-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <bean id="userDAO" class="Spring_jdbc.UserDAOImpl">
        <property name="jdbcTemplate" ref="jdbcTemplate"/>
    </bean>

</beans>

这里引入了dbproperties

driverClass=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql://localhost:3306/user?useSSL=false&useUnicode=true&characterEncoding=UTF-8
user=root
password=123456

之后是设置User对象类

package Spring_jdbc;

public class User {
    private int id;
    private String name;
    private String email;

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getEmail() {
        return email;
    
    public void setEmail(String email) {
        this.email = email;
    
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

这里遇见一个坑,之前查询语句之后出现的是一串数字,不是文字,这里是因为没有使用toString

之后是写接口

public interface UserDAO {
    public void addUser(User user);
    public void delateUser(int id);
    public void updateUser(User user);
    public String queryById(int id);
    public User queryAllById(int id);
    public List<User> findAll();
}

之后是接口实现类

public class UserDAOImpl extends JdbcDaoSupport implements UserDAO {
    ApplicationContext apx = null;
    UserDAO dao=null;

    public void UserDAOSpringImpl(){
        apx=new ClassPathXmlApplicationContext("applicationContext.xml");
        dao=(UserDAO) apx.getBean("userDAO");
    }
    public void addUser(User user) {
        String sql = "insert into demo values(?,?,?)";
        this.getJdbcTemplate().update(sql, user.getId(), user.getName(), user.getEmail());
    }

    public void delateUser(int id) {
        String sql = "delete from demo where id =?";
        this.getJdbcTemplate().update(sql, id);
    }

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

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

    public User queryAllById(int id) {
        String sql = "select * from demo where id=?";
        return this.getJdbcTemplate().queryForObject(sql, new UserRowMapper(),id);
    }

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

使用的是增删改查的测试

@Test
public void addTest(){
    User user=new User();
    user.setId(4);
    user.setName("赵四");
    user.setEmail("rr@rr");
    ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
    UserDAO dao=(UserDAO) apx.getBean("userDAO");
    dao.addUser(user);
}
@Test
public void deleteTest(){
    ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
    UserDAO dao=(UserDAO) apx.getBean("userDAO");
    dao.delateUser(4);
}
@Test
public void updateTest(){
    User user=new User();
    user.setId(4);
    user.setName("熊大");
    user.setEmail("tt@tt");
    ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
    UserDAO dao=(UserDAO) apx.getBean("userDAO");
    dao.updateUser(user);
}
@Test
public void queryByIdTest(){
    ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
    UserDAO dao=(UserDAO) apx.getBean("userDAO");
    String name=dao.queryById(2);
    System.out.println(name);
}
@Test
public void queryALlById(){
    ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
    UserDAO dao=(UserDAO) apx.getBean("userDAO");
    User user=dao.queryAllById(2);
    System.out.println(user);
}
@Test
public void findAll(){
    ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
    UserDAO dao=(UserDAO) apx.getBean("userDAO");
    List<User> users=dao.findAll();
    System.out.println(users);

}

这里代码重复了

ApplicationContext apx=new ClassPathXmlApplicationContext("applicationContext.xml");
UserDAO dao=(UserDAO) apx.getBean("userDAO");

之前看教程是使用DAOFactory

不过DAOFactory实现有问题

明天计划的事情：

使用dbcp和c3p0连接池

遇到的问题： 

不会使用DAOFactory
收获：

知道了如何使用默认连接池对数据库进行增删改查