[Java知识库]Spring JdbcTemplate

前言

什么是Jdbc？
什么是JDBC?这篇文章告诉你在web开发中，不可避免的地要使用数据库来存储和管理数据。为了在java语言中提供数据库访问的支持，Sun公司于1996年提供了—套访问数据的标准Java类库，即JDBC。JDBC的全称是Java数据库连接(Java Databaseconnect)，它是—套用于执行SQL语句的Java APl。应用程序可通过这套API连接到关系数据库，并使用SQL语句来完成对数据库中数据增删改查

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

（1）引入相关jar包

（2）在spring配置文件配置数据库连接池
（3）注入JdbcTemplate对象，注入DataSource

代码示例：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--组件扫描-->
    <context:component-scan base-package="com.aop"></context:component-scan>

    <!--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="2022"/>
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    </bean>
    <!--JdbcTemplate对象-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <!--注入dataSource-->
        <property name="dataSource" ref="dataSource"></property>
    </bean>
</beans>

（4）创建service类,在service类注入dao接口，创建dao类，在dao注入jdbcTemplate对象，及实体类
假设我们要操作这个t_book数据库：

代码示例（创建BookService 类，BookDao接口，BookDaoImpl类）：

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
}

BookDao:

public interface BookDao {}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
 }

Book:

public class Book {
    private String userId;
    private String username;
    private String ustatus;

    public String getUserId() {
        return userId;
    }

    public String getUsername() {
        return username;
    }

    public String getUstatus() {
        return ustatus;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public void setUstatus(String ustatus) {
        this.ustatus = ustatus;
    }

    @Override
    public String toString() {
        return "Book{" +
                "userId='" + userId + '\'' +
                ", username='" + username + '\'' +
                ", ustatus='" + ustatus + '\'' +
                '}';
    }
}

JdbcTemplate增加操作

单个增加

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
 	//添加的方法
    public void addBook(Book book){
        bookDao.add(book);
    }
}

BookDao:

public interface BookDao {
    //添加的方法
    void add(Book book);
}

BookDaoImpl:

@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：

public class TestBook {

    @Test
    public void testJdbcTemplate(){
        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");
        BookService bookService = context.getBean("bookService", BookService.class);
        //添加
        Book book = new Book();
        book.setUserId("1");
        book.setUsername("java");
        book.setUstatus("a");
        bookService.addBook(book);
    }
}

运行结果：

批量增加

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
	  //批量添加
    public void  batchAdd(List<Object[]> batchArgs){
         bookDao.batchAddBook(batchArgs);
    }
}

BookDao:

public interface BookDao {
	//批量添加
    void batchAddBook(List<Object[]> batchArgs);
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
   //批量添加
    @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));
    }
 }

JdbcTemplate删除操作

单个删除

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
    //删除的方法
    public void deleteBook(String id){
        bookDao.delete(id);
    }
}

BookDao:

public interface BookDao {
	 //删除的方法
    void delete(String id);
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
	//删除的方法
    @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);
    }

 }

批量删除

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
	//批量删除
    public void batchDelete(List<Object[]> batchArgs){
        bookDao.batchDeleteBook(batchArgs);
    }
}

BookDao:

public interface BookDao {
 	//批量删除
    void batchDeleteBook(List<Object[]> batchArgs);
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
    //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));
    }
 }

JdbcTemplate修改操作

单个修改

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
	//修改的方法
    public void update(Book book){
        bookDao.updateBook(book);
    }
}

BookDao:

public interface BookDao {
 	//修改的方法
    void updateBook(Book book);
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
    //修改的方法
    @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);
    }
 }

批量修改

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
	//批量修改
    public void batchUpdate(List<Object[]> batchArgs){
        bookDao.batchUpdateBook(batchArgs);
    }
}

BookDao:

public interface BookDao {
	//批量修改
    void batchUpdateBook(List<Object[]> batchArgs);
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
   //批量修改
    @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));
    }
 }

JdbcTemplate查询操作

查询表记录数

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
    //查询表记录数
    public int findCount(){
       return bookDao.selectCount();
    }
}

BookDao:

public interface BookDao {
	//查询表记录数
    int selectCount();
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
    //查询表记录数
    @Override
    public int selectCount() {
        String sql = "select count(*) from t_book";
       Integer count =  jdbcTemplate.queryForObject(sql,Integer.class);
        return count;
    }
 }

查询返回对象

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
    //查询返回对象
    public Book findOne(String id){
        return bookDao.findBookInfo(id);
    }
}

BookDao:

public interface BookDao {
    //查询返回对象
    Book findBookInfo(String id);
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
        //查询返回对象
    @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;
    }
 }

查询返回集合

BookService:

public class BookService {
	//注入dao
    @Autowired
    private BookDao bookDao;
    //查询返回集合
    public List<Book> findAll(){
        return bookDao.findAllBook();
    }
}

BookDao:

public interface BookDao {
   //查询返回集合
    List<Book> findAllBook();
}

BookDaoImpl:

@Repository
public class BookDaoImpl implements  BookDao{

    //注入jdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
    //查询返回集合
    @Override
    public List<Book> findAllBook() {
        String sql = "select * from t_book";
        List<Book> bookList = jdbcTemplate.query(sql, new BeanPropertyRowMapper<Book>(Book.class));
        return bookList;
    }
 }