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。
如何使用
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
1 | < bean id = "dataSource" class = "com.alibaba.druid.pool.DruidDataSource" destroy-method = "close" >< property name = "url" value = "jdbc:mysql:///user_db" ></ property >< property name = "username" value = "root" ></ property >< property name = "password" value = "root" ></ property >< property name = "driverClassName" value = "com.mysql.jdbc.Driver" ></ property ></ bean > |
3.配置 JdbcTemplate 对象,注入 DataSource
1 | < bean id = "jdbcTemplate" class = "org.springframework.jdbc.core.JdbcTemplate" >< property name = "dataSource" ref = "dataSource" ></ property ></ bean > |
5.配置文件里开启组件扫描
1 | < component-scan base-package = "com.atguigu" ></ component-scan > |
6.创建 service 类,创建 dao 类,在 dao 注入 jdbcTemplate 对象
service
1 2 3 4 5 6 | @Service public class BookService { //注入 dao @Autowired private BookDao bookDao; } |
dao
1 2 3 4 5 6 | @Repository public class BookDaoImpl implements BookDao { //注入 JdbcTemplate @Autowired private JdbcTemplate jdbcTemplate; } |
数据库表对应的实体类
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | 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; } } |
数据库操作
添加
dao:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | @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:
1 2 3 4 5 6 7 8 9 10 11 12 | @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); } |
修改
dao增加
1 2 3 4 5 6 7 | @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); } |
删除
dao增加
1 2 3 4 5 6 | @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); } |
查询
1.返回某个值
dao增加
1 2 3 4 5 6 | @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
1 2 3 4 5 6 7 8 9 | @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; } </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
1 2 3 4 5 6 7 8 9 | @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; } </book></book></book> |
批量操作
1.批量修改
dao增加
1 2 3 4 5 6 7 | @Override public void batchAddBook(List<object data-origwidth= "" data-origheight= "" style= "width: 1264px;" > batchArgs) { String sql = "insert into t_book values(?,?,?)" ; int [] ints = jdbcTemplate.batchUpdate(sql, batchArgs); System.out.println(Arrays.toString(ints)); } </object> |
测试:
1 2 3 4 5 6 7 8 9 10 | List<object data-origwidth= "" data-origheight= "" style= "width: 1264px;" > 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); </object> |
2.批量
dao增加
1 2 3 4 5 6 7 | @Override public void batchUpdateBook(List<object data-origwidth= "" data-origheight= "" style= "width: 1264px;" > batchArgs) { String sql = "update t_book set username=?,ustatus=? where user_id=?" ; int [] ints = jdbcTemplate.batchUpdate(sql, batchArgs); System.out.println(Arrays.toString(ints)); } </object> |
3.批量删除
1 2 3 4 5 6 7 | @Override public void batchDeleteBook(List<object data-origwidth= "" data-origheight= "" style= "width: 1264px;" > batchArgs) { String sql = "delete from t_book where user_id=?" ; int [] ints = jdbcTemplate.batchUpdate(sql, batchArgs); System.out.println(Arrays.toString(ints)); } </object> |
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