基本概念

• Spring框架對JDBC進行封裝，使用JdbcTemplate方便實現對資料庫操作

準備工作

• 匯入依賴

  <dependencies>
      <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.6</version>
          <scope>runtime</scope>
      </
   
  dependency>
      <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.13</version>
          <scope>test</scope>
      </dependency>
      <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
   
  
      <dependency>
          <groupId>com.alibaba</groupId>
          <artifactId>druid</artifactId>
          <version>1.2.3</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</
   
  artifactId>
          <version>5.0.6.RELEASE</version>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-jdbc</artifactId>
          <version>5.1.2.RELEASE</version>
      </dependency>
      <dependency>
          <groupId>log4j</groupId>
          <artifactId>log4j</artifactId>
          <version>1.2.14</version>
      </dependency>
      <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
      <dependency>
          <groupId>org.projectlombok</groupId>
          <artifactId>lombok</artifactId>
          <version>1.18.12</version>
          <scope>provided</scope>
      </dependency>
  </dependencies>
  

• 名稱空間

  <?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
  ">
  

• spring配置檔案配置資料庫連線池

  <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url">
          <value> <![CDATA[jdbc:mysql://localhost:3306/spring?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&rewriteBatchedStatements=true]]></value>
      </property>
      <property name="username" value="root"/>
      <property name="password" value="root"/>
  </bean>
  

• 配置JdbcTemplate物件，注入DataSource

  <bean class="org.springframework.jdbc.core.JdbcTemplate" id="jdbcTemplate">
      <property name="dataSource" ref="dataSource"/>
  </bean>
  

• 開啟元件掃描

  <context:component-scan base-package="com.du.spring"/>
  

• 檔案結構
  
• pojo/bean

  @Data
  @AllArgsConstructor
  @NoArgsConstructor
  public class User {
    private int id;
    private String username;
    private String phone;
  }
  

• 編寫Dao和Service

  public interface UserDao {
    int addUser(User user);
  }
  

  // 一般用於持久層（DAO）
  @Repository
  public class UserDaoImpl implements UserDao {
    @Autowired
    JdbcTemplate jdbcTemplate;   // 自動裝配
  
    @Override
    public int addUser(User user) {
      String sql = "insert into user_info(username, phone) values(?,?);";
      return jdbcTemplate.update(sql, user.getUsername(), user.getPhone());
    }
  }
  

  public interface UserService {
    int addUser(User user);
  }
  

  // 一般用Service建立物件
  @Service
  public class UserServiceImpl implements UserService {
    @Autowired
    private UserDao userDaoImpl;
  
    @Override
    public int addUser(User user) {
      return userDaoImpl.addUser(user);
    }
  }
  

• 測試類

  public class Demo {
    private static final Logger logger = Logger.getLogger(Demo.class);
    @Test
    public void test() {
      ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
      UserService userServiceImpl = context.getBean("userServiceImpl", UserServiceImpl.class);
      int res = userServiceImpl.addUser(new User("jhon", "1434314"));
      if (res > 0)
        logger.info("新增成功");
      else
        logger.info("新增失敗");
    }
  }
  

CRUD

• 查詢返回某個值

  @Override
    public int countUser() {
      String sql = "select count(*) from user_info";
      Integer res = jdbcTemplate.queryForObject(sql, Integer.class);
      if (res != null) return res;
      throw new RuntimeException("查不到");
    }
  

• 查詢某個物件

    @Override
    public User selectUserById(int id) {
      String sql = "select * from user_info where id = ?";
      User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(User.class), id);
      if (user != null) return user;
      throw new RuntimeException("查不到");
    }
  

  RowMapper 是介面，針對返回不同型別資料，使用這個接口裡面實現類完成資料封裝

• 查詢一個集合包含多個物件

  @Override
    public List<User> selectUsers() {
      String sql = "select id, username, phone from user_info";
      // RowMapper 是介面，針對返回不同型別資料，使用這個接口裡面實現類完成資料封裝
      return jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(User.class));
    }
  

  RowMapper 是介面，針對返回不同型別資料，使用這個接口裡面實現類完成資料封裝

• 刪除

    @Override
    public int deleteUserById(int id) {
      String sql = "delete from user_info where id = ?";
      return jdbcTemplate.update(sql, id);
    }
  

• 更新

    @Override
    public int updateUser(User user) {
      String sql = "update user_info set username = ?, phone = ? where id = ?;";
      return jdbcTemplate.update(sql, user.getUsername(), user.getPhone(), user.getId());
    }
  

批量操作

• 批量操作：操作表裡面多條記錄
• 批量增加

  @Override
    public void batchAddUsers(List<Object[]> batchArgs) {
      String sql = "insert into user_info(username, phone) values(?,?);";
      // 批量執行sql,並傳入多個數組組成的引數
      int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
      System.out.println(Arrays.toString(ints));
    }
  

    @Test
    public void batchAddUsersTest() {
      List<Object[]> batchArgs = new ArrayList<>();
      Object[] o1 = {"nihao", "458785"};
      Object[] o2 = {"shijie", "458785"};
      batchArgs.add(o1);
      batchArgs.add(o2);
      userServiceImpl.batchAddUsers(batchArgs);
    }
  

• 批量更新

    @Override
    public void batchUpdateUsers(List<Object[]> batchArgs) {
      String sql = "update user_info set username = ?, phone = ? where id = ?;";
      // 批量執行sql,並傳入多個數組組成的引數
      int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
      System.out.println(Arrays.toString(ints));
    }
  

    @Test
    public void batchUpdateUsersTest() {
      List<Object[]> batchArgs = new ArrayList<>();
      Object[] o1 = {"nihao", "458785", 5};
      Object[] o2 = {"shijie", "458785", 6};
      batchArgs.add(o1);
      batchArgs.add(o2);
      userServiceImpl.batchUpdateUsers(batchArgs);
    }
  

• 批量刪除

    @Override
    public void batchDeleteUsers(List<Object[]> batchArgs) {
      String sql = "delete from user_info where id = ?";
      // 批量執行sql,並傳入多個數組組成的引數
      int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
      System.out.println(Arrays.toString(ints));
    }
  

    @Test
    public void batchDeleteUsersTest() {
      List<Object[]> batchArgs = new ArrayList<>();
      Object[] o1 = {5};
      Object[] o2 = {6};
      batchArgs.add(o1);
      batchArgs.add(o2);
      userServiceImpl.batchDeleteUsers(batchArgs);
    }