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什麼是JDBCTemplate?
- Spring框架對JDBC進行封裝,使用JDBCTemplate方便實現對數據的操作
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準備工作
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引入相關的依賴
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在Spring配置文件配置數據庫連接池
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close"> <property name="url" value="jdbc:mysql://localhost:3306"/> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="username" value="root"/> <property name="password" value="154269564"/> </bean>
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配置JDBCTemplate對象,注入dataSource
<!-- jdbcTemplate對象--> <bean id="JdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <!-- 注入dataSource--> <!-- JdbcTemplate源碼中,使用的set注入--> <property name="dataSource" value="dataSource"/> </bean>
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創建service類,創建dao類,在dao注入jdbcTemplate對象
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application.xml配置文件
<!-- 開啓組件掃描--> <context:component-scan base-package="com.qi"></context:component-scan>
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Dao
public interface BookDao { }
@Repository public class BookDaoImpl implements BookDao{ //注入jdbcTemplate @Autowired JdbcTemplate jdbcTemplate; }
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Service
@Service public class BookService { //注入Dao @Autowired BookDao bookDo; }
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JDBCTempl操作數據庫(添加)
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對應數據庫創建實體類
@Data @AllArgsConstructor @NoArgsConstructor public class User { private int userId; private String username; private String ustatus; }
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編寫Service和Dao
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在dao進行數據庫添加操作
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調用JDBCTemplate對象中的update方法實現添加操作
- 有兩個參數
- 第一個參數,sql語句
- 第二個參數:可變參數,設置sql語句值
public interface UserDao { public void add(User user); }
@Repository public class UserDaoImpl implements UserDao { //注入jdbcTemplate @Autowired JdbcTemplate jdbcTemplate; public void add(User user) { //創建sql語句 String string = "insert into t_user values(?,?,?)"; // //調用方法實現 Object[] args = {user.getUserId(),user.getUsername(),user.getUstatus()};//可變參數 int update = jdbcTemplate.update(string, args); System.out.println(update); } }
public interface UserService { public void add(User user); }
@Service("UserService")//變爲一個UserService的bean public class UserServiceImpl implements UserService{ @Autowired UserDao userDao; public void add(User user) { userDao.add(user); } }
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測試類
public class TestDemo { @Test public void TestUser(){ ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); UserServiceImpl userService = context.getBean("UserService", UserServiceImpl.class); User user = new User(); user.setUserId(Integer.parseInt("3")); user.setUsername("zhangsan"); user.setUstatus("a"); userService.add(user); } }
JDBCTempl操作數據庫(添加)
public void update(User user) {//修改 //創建sql語句 String string = "update t_user set username=?,ustatus=? where user_id=?"; //調用方法實現 Object[] args = {user.getUsername(),user.getUstatus(),user.getUserId()};//可變參數 int update = jdbcTemplate.update(string, args); System.out.println(update); } public void delete(int id) {//刪除 //創建sql語句 String string = "delete from t_user where user_id=?"; //調用方法實現 int delete = jdbcTemplate.update(string, id); System.out.println(delete); }
測試類:
@Test public void Test_Update(){ ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); UserServiceImpl userService = context.getBean("UserService", UserServiceImpl.class); User user = new User(); user.setUserId(Integer.parseInt("3")); user.setUsername("lisi"); user.setUstatus("b"); userService.update(user); } @Test public void Test_Delete(){ ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); UserServiceImpl userService = context.getBean("UserService", UserServiceImpl.class); userService.delete(2); }
JDBCTempl操作數據庫(查詢返回某個值)
- 兩個參數
- 參數1:sql語句
- 參數2:返回類型Class
//查詢表中的記錄數 public int selectCount() { String sql = "select count(*) from t_user"; Integer query = jdbcTemplate.queryForObject(sql, Integer.class); return query; }
@Test public void Test_Query(){ ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml"); UserServiceImpl userService = context.getBean("UserService", UserServiceImpl.class); int count = userService.selectCount(); System.out.println(count); }
JDBCTempl操作數據庫(查詢返回對象)
- 場景:查詢圖書詳情(返回一個Book對象)
- JDBCTempl實現查詢返回對象
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- 三個參數
- 參數1:sql語句
- 參數2:RowMapper,是一個接口,返回不同類型數據,時用這個接口裏面實現類完成數據的封裝
- 參數3:可變參數,sql語句值
public User findUser(int id) {
String sql = "select * from t_user where user_id=?";
User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
return user;
}
@Test
public void Test_findUser(){
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserServiceImpl userService = context.getBean("UserService", UserServiceImpl.class);
User user = userService.findUser(1);
System.out.println(user);
}
JDBCTempl操作數據庫(查詢返回集合)
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場景:查詢圖書列表分頁
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JDBCTempl實現查詢返回集合
- 三個參數:
- 參數1:sql語句
- 參數2:RowMapper,是一個接口,返回不同類型數據,時用這個接口裏面實現類完成數據的封裝
- 參數3;sql語句值,可以省略不寫
public List<User> findAllUser() {
String sql = "select * from t_user";
List<User> query = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
return query;
}
@Test
public void Test_findAllUser(){
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserServiceImpl userService = context.getBean("UserService", UserServiceImpl.class);
List<User> allUser = userService.findAllUser();
System.out.println(allUser);
}