说明：基于atguigu笔记。
JdbcTemplate 是 Spring 对 JDBC 的封装，目的是使JDBC更加易于使用，JdbcTemplate是Spring的一部分。JdbcTemplate 处理了资源的建立和释放，它帮助我们避免一些常见的错误，比如忘了总要关闭连接。他运行核心的JDBC工作流，如Statement的建立和执行，而我们只需要提供SQL语句和提取结果即可。
准备工作：
1.引入相关 jar 包
druid.java、mysql-connector-java.jar、spring-jdbc.java、spring-orm.java、spring-tx.java。
2.在 spring 配置文件配置数据库连接池
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close"> <property name="url" value="jdbc:mysql:///user_db" /> <property name="username" value="root" /> <property name="password" value="root" /> <property name="driverClassName" value="com.mysql.jdbc.Driver" /> </bean>
3.配置 JdbcTemplate 对象，注入 DataSource
<!-- JdbcTemplate 对象 --> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <!--注入 dataSource--> <property name="dataSource" ref="dataSource"></property> </bean>
5.配置文件里开启组件扫描
<!-- 组件扫描 --> <context:component-scan base-package="com.atguigu"></context:component-scan>
6.创建 service 类，创建 dao 类，在 dao 注入 jdbcTemplate 对象
service
@Service
public class BookService {
//注入 dao
@Autowired
private BookDao bookDao;
}
dao
@Repository
public class BookDaoImpl implements BookDao {
//注入 JdbcTemplate
@Autowired
private JdbcTemplate jdbcTemplate;
}
数据库表对应的实体类
public class UserT {
private String userId;
private String username;
private String ustatus;
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this.userId = userId;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getUstatus() {
return ustatus;
}
public void setUstatus(String ustatus) {
this.ustatus = ustatus;
}
}dao：
@Repository
public class BookDaoImpl implements BookDao {
//注入 JdbcTemplate
@Autowired
private JdbcTemplate jdbcTemplate;
//添加的方法
@Override
public void add(Book book) {
//1 创建 sql 语句
String sql = "insert into t_book values(?,?,?)";
//2 调用方法实现
Object[] args = {book.getUserId(), book.getUsername(), book.getUstatus()};
int update = jdbcTemplate.update(sql,args);
System.out.println(update);
}
}测试类：
@Test
public void testJdbcTemplate() {
ApplicationContext context =
new ClassPathXmlApplicationContext("bean1.xml");
BookService bookService = context.getBean("bookService",
BookService.class);
Book book = new Book();
book.setUserId("1");
book.setUsername("java");
book.setUstatus("a");
bookService.addBook(book);
}dao增加
@Override
public void updateBook(Book book) {
String sql = "update t_book set username=?,ustatus=? where user_id=?";
Object[] args = {book.getUsername(), book.getUstatus(),book.getUserId()};
int update = jdbcTemplate.update(sql, args);
System.out.println(update);
}
dao增加
@Override
public void delete(String id) {
String sql = "delete from t_book where user_id=?";
int update = jdbcTemplate.update(sql, id);
System.out.println(update);
}
1.返回某个值
dao增加
@Overridepublic int selectCount() {<!--{cke_protected}{C}%3C!%2D%2D%20%2D%2D%3E-->String sql = "select count(*) from t_book";Integer count = jdbcTemplate.queryForObject(sql, Integer.class);return count;}@Override
public int selectCount() {
String sql = "select count(*) from t_book";
Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
return count;
}
2.返回对象
dao增加
@Override
public Book findBookInfo(String id) {
String sql = "select * from t_book where user_id=?";
//调用方法
Book book = jdbcTemplate.queryForObject(sql, new
BeanPropertyRowMapper<Book>(Book.class), id);
return book;
}
RowMapper 是接口，针对返回不同类型数据，使用这个接口里面实现类完成
数据封装。
3.返回集合
dao增加
@Override
public List<Book> findAllBook() {
String sql = "select * from t_book";
//调用方法
List<Book> bookList = jdbcTemplate.query(sql, new
BeanPropertyRowMapper<Book>(Book.class));
return bookList;
}
1.批量修改
dao增加
@Override
public void batchAddBook(List<Object[]> batchArgs) {
String sql = "insert into t_book values(?,?,?)";
int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
System.out.println(Arrays.toString(ints));
}
测试：
List<Object[]> batchArgs = new ArrayList<>();
Object[] o1 = {"3","java","a"};
Object[] o2 = {"4","c++","b"};
Object[] o3 = {"5","MySQL","c"};
batchArgs.add(o1);
batchArgs.add(o2);
batchArgs.add(o3);
//调用批量添加
bookService.batchAdd(batchArgs);
2.批量
dao增加
@Override
public void batchUpdateBook(List<Object[]> batchArgs) {
String sql = "update t_book set username=?,ustatus=? where user_id=?";
int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
System.out.println(Arrays.toString(ints));
}
3.批量删除
@Override
public void batchDeleteBook(List<Object[]> batchArgs) {
String sql = "delete from t_book where user_id=?";
int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
System.out.println(Arrays.toString(ints));
}
