JdbcTemplate（概念和准备）
什么是JdbcTemplate
Spring框架对JDBC进行封装，使用JdbcTemplate方便实现对数据库操作
准备工作
引入相关的jar包
<dependencies><!--单元测试--><!-- https://mvnrepository.com/artifact/junit/junit --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><scope>test</scope></dependency><!--spring核心包--><!-- https://mvnrepository.com/artifact/commons-logging/commons-logging --><dependency><groupId>commons-logging</groupId><artifactId>commons-logging</artifactId><version>1.1.1</version></dependency><!-- https://mvnrepository.com/artifact/org.springframework/spring-context --><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.8.RELEASE</version></dependency><!-- https://mvnrepository.com/artifact/org.springframework/spring-core --><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>5.2.8.RELEASE</version></dependency><!-- https://mvnrepository.com/artifact/org.springframework/spring-beans --><dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>5.2.8.RELEASE</version></dependency><!-- https://mvnrepository.com/artifact/org.springframework/spring-expression --><dependency><groupId>org.springframework</groupId><artifactId>spring-expression</artifactId><version>5.2.8.RELEASE</version></dependency><!--Spring框架一般都是基于AspectJ实现AOP操作--><!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects --><dependency><groupId>org.springframework</groupId><artifactId>spring-aspects</artifactId><version>5.2.8.RELEASE</version></dependency><!--JdbcTemplate操作依赖的包，事务好像也是包含在这个里面的--><!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc --><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.2.8.RELEASE</version></dependency><!--注解导入的包--><!-- https://mvnrepository.com/artifact/org.springframework/spring-aop --><dependency><groupId>org.springframework</groupId><artifactId>spring-aop</artifactId><version>5.2.8.RELEASE</version></dependency><!--德鲁伊数据库连接池--><!-- https://mvnrepository.com/artifact/com.alibaba/druid --><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.9</version></dependency><!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency></dependencies>
在spring配置文件配置数据库连接池
<!--数据库连接池-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="url" value="jdbc:mysql://localhost:3306/test"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
</bean>
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>
创建service类，创建dao类，在dao注入jdbcTemplate对象
配置文件
<!--开启组件扫描-->
<context:component-scan base-package="com.zh"></context:component-scan>
Service
@Service
public class BookService {
// 注入dao
@Autowired
private BookDao bookDao;
}
Dao
@Repository
public class BookDaoImpl implements BookDao {
// 注入JdbcTemplate对象
@Autowired
private JdbcTemplate jdbcTemplate;
}
JdbcTemplate操作数据库（添加）
对应数据库创建实体类
public class Book {
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;
}
}
编写service和dao
- 在dao进行数据添加操作
- 调用JdbcTemplate对象里面update方法实现添加操作
- 有两个参数
- 第一个参数：sql语句
- 第二个参数：可变参数，设置sql语句值
@Repository
public class BookDaoImpl implements BookDao {
// 注入JdbcTemplate对象
@Autowired
private JdbcTemplate jdbcTemplate;
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
@org.junit.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);
}
JdbcTemplate操作数据库（修改和删除）
修改
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
public void deleteBook(String id) {
String sql = "delete from t_book where user_id = ?";
int update = jdbcTemplate.update(sql, id);
System.out.println(update);
}
JdbcTemplate操作数据库（查询返回某个值）
- 查询表里面有多少条记录，返回是某个值
- 使用JdbcTemplate实现查询返回某个值代码
- 有两个参数
- 第一个参数：sql语句
- 第二个参数：返回类型Class
@Override
public int selectBook() {
String sql = "select count(*) from t_book";
Integer count = jdbcTemplate.queryForObject(sql, Integer.class);
return count;
}
JdbcTemplate操作数据库（查询返回对象）
- 场景：查询图书详情
- JdbcTemplate实现传返回对象
- 有三个参数
- 第一个参数：sql语句
- 第二个参数：RowMapper是接口，针对返回不同类型数据，使用这个接口里卖弄实现类完成数据封装
- 第三个参数：sql语句值
@Override
public Book findBookInfo(String id) {
String sql = "select * from t_book where user_id = ?";
Book book = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<Book>(Book.class), id);
return book;
}
JdbcTemplate操作数据库（查询返回集合）
- 场景：查询图书列表分页
- 调用JdbcTemplate方法实现查询返回集合
- 有三个参数
- 第一个参数：sql语句
- 第二个参数：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
- 第三个集合：sql语句值
@Override
public List<Book> findAllBook() {
String sql = "select * from t_book";
List<Book> query = jdbcTemplate.query(sql, new BeanPropertyRowMapper<Book>(Book.class));
return query;
}
JdbcTemplate操作数据库（批量操作）
批量操作：操作表里面多条记录
JdbcTemplate实现批量添加数据
- 有两个参数
- 第一个参数：sql语句
- 第二个参数：List集合，添加多条数据记录
@Override
public void batchAddBook(List<Object[]> batchArgs) {
String sql = "insert into t_book value(?, ?, ?)";
int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
System.out.println(Arrays.toString(ints));
}
// 批量添加测试
List<Object[]> batchArgs = new ArrayList<>();
Object[] o1 = {"4", "java", "b"};
Object[] o2 = {"5", "java", "c"};
Object[] o3 = {"6", "java", "d"};
batchArgs.add(o1);
batchArgs.add(o2);
batchArgs.add(o3);
bookService.batchAddBook(batchArgs);
JdbcTemplate实现批量修改操作
@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));
}
List<Object[]> batchArgs = new ArrayList<>();
Object[] o1 = {"java0909", "b1", "4"};
Object[] o2 = {"java0909", "c1", "5"};
Object[] o3 = {"java0909", "d1", "6"};
batchArgs.add(o1);
batchArgs.add(o2);
batchArgs.add(o3);
bookService.batchUpdateBook(batchArgs);
JdbcTemplate实现批量删除数据
@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));
}
List<Object[]> batchArgs = new ArrayList<>();
Object[] o1 = {"3"};
Object[] o2 = {"4"};
batchArgs.add(o1);
batchArgs.add(o2);
bookService.batchDeleteBook(batchArgs);
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