JdbcTemplate

JdbcTemplate JdbcTemplate概念及使用

1、什么是 JdbcTemplate

（1）Spring 框架对 JDBC 进行封装，使用 JdbcTemplate 方便实现对数据库操作

2、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）配置 JdbcTemplate 对象，注入 DataSource

（4）创建 service 类，创建 dao 类，在 dao 注入 jdbcTemplate 对象

package com.atguigu.spring.service;

import com.atguigu.spring.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class BookService {

    //注入dao
    @Autowired
    private BookDao bookDao;

}

package com.atguigu.spring.dao;

public interface BookDao {

}

package com.atguigu.spring.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository
public class BookDaoImpl implements BookDao {

    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;
}

JdbcTemplate操作数据库—添加功能

1、对应数据库创建实体类

2、编写 service 和 dao

（1）在 dao 进行数据库添加操作

（2）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

package com.atguigu.spring.entity;

public class Book {

    private String userid;
    private String username;
    private String 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;
    }

    public String getUserid() {
        return userid;
    }

    public String getUsername() {
        return username;
    }

    public String getUstatus() {
        return ustatus;
    }
}

@Service
public class BookService {

    //注入dao
    @Autowired
    private BookDao bookDao;

    //添加的方法
    public void addBook(Book book) {
        bookDao.add(book);
    }

}

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

@Repository
public class BookDaoImpl implements BookDao {

    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;

    //添加的方法
    @Override
    public void add(Book book) {

        String sql = "insert into t_book value(?,?,?)";

        Object[] args = {book.getUserid(), book.getUsername(), book.getUstatus()};
        int update = jdbcTemplate.update(sql,args);

        System.out.println(update);
    }
}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        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—修改删除

@Service
public class BookService {

    //注入dao
    @Autowired
    private BookDao bookDao;

    //添加的方法
    public void addBook(Book book) {
        bookDao.add(book);
    }

    //修改的方法
    public void updateBook(Book book) {
        bookDao.updateBook(book);
    }

    //删除的方法
    public void delete(String id) {
        bookDao.delete(id);
    }

}

package com.atguigu.spring.dao;

import com.atguigu.spring.entity.Book;

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

    //修改的方法
    void updateBook(Book book);

    //删除的方法
    void delete(String id);
}

@Repository
public class BookDaoImpl implements BookDao {

    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;

    //添加的方法
    @Override
    public void add(Book book) {

        String sql = "insert into t_book value(?,?,?)";

        Object[] args = {book.getUserid(), book.getUsername(), book.getUstatus()};
        int update = jdbcTemplate.update(sql,args);

        System.out.println(update);
    }

    //修改的方法
    @Override
    public void updateBook(Book book) {

        String sql = "update t_book set username=?,ustatus=? where userid=?";

        Object[] args = {book.getUsername(),book.getUstatus(),book.getUserid()};
        int update = jdbcTemplate.update(sql, args);
        System.out.println(update);
    }

    //删除的方法
    @Override
    public void delete(String id) {
        String sql = "delete from t_book where userid=?";
        int update = jdbcTemplate.update(sql, id);
        System.out.println(update);
    }
}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        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);

//        //修改
//        Book book = new Book();
//        book.setUserid("1");
//        book.setUsername("javaup");
//        book.setUstatus("at");
//
//        bookService.updateBook(book);

        //删除
        bookService.delete("1");
    }
}

JdbcTemplate操作数据库—查询查询返回某个值

1、查询表里面有多少条记录，返回是某个值

2、使用 JdbcTemplate 实现查询返回某个值代码

@Service
public class BookService {

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

}

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

@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;
    }

}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");

        BookService bookService = context.getBean("bookService", BookService.class);

        int count = bookService.findCount();
        System.out.println(count);
    }
}

查询返回对象

1、场景：查询图书详情

2、JdbcTemplate 实现查询返回对象

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，使用这个接口里面实现类完成 数据封装 

第三个参数：sql 语句值

@Service
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);
    }

}

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

@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 userid=?";

        Book book = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper(Book.class), id);

        return book;
    }

}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");

        BookService bookService = context.getBean("bookService", BookService.class);

        //查询返回对象
        Book book = bookService.findOne("1");
        System.out.println(book);
    }
}

查询返回集合

1、场景：查询图书列表分页…

2、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 

第三个参数：sql 语句值

@Service
public class BookService {

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

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

@Repository
public class BookDaoImpl implements BookDao {
    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;

    //查询返回集合
    @Override
    public List findAllBook() {

        String sql = "select * from t_book";

        List bookList = jdbcTemplate.query(sql,new BeanPropertyRowMapper(Book.class));
        return bookList;
    }
    
}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");

        BookService bookService = context.getBean("bookService", BookService.class);

        //查询返回集合
        List bookList = bookService.findAll();
        System.out.println(bookList);
    }
}

JdbcTemplate操作数据库—批量操作

1、批量操作：操作表里面多条记录

JdbcTemplate 实现批量添加操作

有两个参数

第一个参数：sql 语句

第二个参数：List 集合，添加多条记录数据

@Service
public class BookService {

    //注入dao
    @Autowired
    private BookDao bookDao;

    //批量添加
    public void batchAdd(List batchArgs) {

        bookDao.batchAddBook(batchArgs);
    }
}

public interface BookDao {

    //批量添加
    void batchAddBook(List batchArgs);
}

@Repository
public class BookDaoImpl implements BookDao {
    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;

    //批量添加
    @Override
    public void batchAddBook(List batchArgs) {

        String sql = "insert into t_book value(?,?,?)";

        int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
        System.out.println(Arrays.toString(ints));
    }

}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");

        BookService bookService = context.getBean("bookService", BookService.class);

        //批量添加
        List 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);

        bookService.batchAdd(batchArgs);

    }
}

JdbcTemplate 实现批量修改操作

@Service
public class BookService { 
//批量修改
    public void batchUpdate(List batchArgs) {

        bookDao.batchUpdateBook(batchArgs);
    }
}

public interface BookDao {    

    //批量修改
    void batchUpdateBook(List batchArgs);
}

@Repository
public class BookDaoImpl implements BookDao {
    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;  

    //批量修改
    @Override
    public void batchUpdateBook(List batchArgs) {
        String sql = "update t_book set username=?,ustatus=? where userid=?";

        int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
        System.out.println(Arrays.toString(ints));
    }

}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");

        BookService bookService = context.getBean("bookService", BookService.class);

        //批量修改
        List batchArgs = new ArrayList<>();
        Object[] O1 = {"java0909","a3","3"};
        Object[] O2 = {"C++1010","b4","4"};
        Object[] O3 = {"MySQL1111","c5","5"};
        batchArgs.add(O1);
        batchArgs.add(O2);
        batchArgs.add(O3);

        bookService.batchUpdate(batchArgs);
    }
}

JdbcTemplate 实现批量删除操作

import java.util.List;

@Service
public class BookService {

    //注入dao
    @Autowired
    private BookDao bookDao;    

    //批量删除
    public void batchDelate(List batchArgs) {

        bookDao.batchDelateBook(batchArgs);
    }
}

public interface BookDao {
    
    //批量删除
    void batchDelateBook(List batchArgs);
}

@Repository
public class BookDaoImpl implements BookDao {
    //注入JdbcTemplate
    @Autowired
    private JdbcTemplate jdbcTemplate;

    //批量删除
    @Override
    public void batchDelateBook(List batchArgs) {

        String sql = "delete from t_book where userid=?";

        int[] ints = jdbcTemplate.batchUpdate(sql, batchArgs);
        System.out.println(Arrays.toString(ints));
    }

}

public class TestBook {

    @Test
    public void testJdbcTempelate() {

        ApplicationContext context =
                new ClassPathXmlApplicationContext("bean1.xml");

        BookService bookService = context.getBean("bookService", BookService.class);
      
        //批量删除
        List batchArgs = new ArrayList<>();
        Object[] O1 = {"3"};
        Object[] O2 = {"4"};
        Object[] O3 = {"5"};
        batchArgs.add(O1);
        batchArgs.add(O2);
        batchArgs.add(O3);

        bookService.batchDelate(batchArgs);
    }
}

JdbcTemplate

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