springmvc工具类封装RowMapper详解编程语言

springmvc通常是先写实体，在数据库查询，最后增删改差，最感觉代码很冗余，自己在封装了一下。

常见的结构是：

entity：如

package com.liuxinquan.entiry; 
 
/** 
 * @author:lxq 
 * @类说明:Book 
 *  
 */ 
public class Book { 
 
	private String id; 
	private String user_id; 
	private String item_id; 
	private String prefer; 
 
	private String time; 
 
	public String getId() { 
		return id; 
	} 
 
	public String getUser_id() { 
		return user_id; 
	} 
 
	public void setUser_id(String user_id) { 
		this.user_id = user_id; 
	} 
 
	public String getItem_id() { 
		return item_id; 
	} 
 
	public void setItem_id(String item_id) { 
		this.item_id = item_id; 
	} 
 
	public String getPrefer() { 
		return prefer; 
	} 
 
	public void setPrefer(String prefer) { 
		this.prefer = prefer; 
	} 
 
	public String getTime() { 
		return time; 
	} 
 
	public void setTime(String time) { 
		this.time = time; 
	} 
 
	public void setId(String id) { 
		this.id = id; 
	} 
 
}

object：如

package com.liuxinquan.object; 
 
import java.sql.ResultSet; 
import java.sql.SQLException; 
 
import org.springframework.jdbc.core.RowMapper; 
 
import com.liuxinquan.entiry.Book; 
 
/** 
 * @author:lxq 
 * @类说明：bookobject 
 *  
 */ 
public class BookObj implements RowMapper<Book> { 
 
	@Override 
	public Book mapRow(ResultSet rs, int arg1) throws SQLException { 
		Book book = new Book(); 
		book.setId(rs.getString("id")); 
		book.setItem_id(rs.getString("item_id")); 
		book.setPrefer(rs.getString("prefer")); 
		book.setTime(rs.getString("time")); 
		book.setUser_id(rs.getString("user_id")); 
		return book; 
	} 
	 
	 
 
}

service

package com.liuxinquan.service; 
 
import java.util.List; 
 
import javax.annotation.Resource; 
 
import org.springframework.jdbc.core.JdbcTemplate; 
import org.springframework.stereotype.Service; 
 
import com.liuxinquan.entiry.Book; 
import com.liuxinquan.utils.CommonObj; 
 
/** 
 * @author: @类说明： 
 *  
 */ 
@Service 
public class BookService { 
	@Resource(name = "jdbcTemplate") 
	public JdbcTemplate jdbcTemplate; 
 
	public List<Book> findAll() { 
		String sql = "select * from recommender_prefer "; 
		List<Book> books = jdbcTemplate.query(sql, new bookObj()); 
		return books; 
	} 
 
	public Book findbyId(String id) { 
		String sql = "select * from recommender_prefer where id =" + id; 
		Book book = jdbcTemplate.queryForObject(sql, new BookObj()); 
		return book; 
	} 
	 
}

下面是简化的工具类

要是有很多实体，每写一个，都要重复这3个，效率很低，其中后两个是可以封装工具类：通用object

package com.liuxinquan.utils; 
 
import java.lang.reflect.Field; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
 
import org.springframework.jdbc.core.RowMapper; 
 
/** 
 * @author:lxq 
 * @类说明：通用dao工具 
 *  
 */ 
public class CommonObj implements RowMapper<Object> { 
 
	private Class<?> cl; 
 
	public CommonObj(Class<?> cl) { 
		this.cl = cl; 
	} 
 
	@Override 
	public Object mapRow(ResultSet rs, int i) throws SQLException { 
 
		try { 
			Field[] fields = cl.getDeclaredFields(); 
			Object entity = cl.newInstance(); 
			for (Field f : fields) { 
				f.setAccessible(true); 
				this.typeMapper(f, entity, rs); 
				f.setAccessible(false); 
			} 
			return entity; 
		} catch (Exception e) { 
			// TODO Auto-generated catch block 
			e.printStackTrace(); 
		} 
		return null; 
	} 
 
	private void typeMapper(Field field, Object obj, ResultSet rs) throws Exception { 
		String type = field.getType().getName(); 
		if (type.equals("java.lang.String")) { 
			field.set(obj, rs.getString(field.getName())); 
		} else if (type.equals("int") || type.equals("java.lang.Integer")) { 
			field.set(obj, rs.getInt(field.getName())); 
		} else if (type.equals("long") || type.equals("java.lang.Long")) { 
			field.set(obj, rs.getLong(field.getName())); 
		} else if (type.equals("boolean") || type.equals("java.lang.Boolean")) { 
			field.set(obj, rs.getBoolean(field.getName())); 
		} else if (type.equals("java.util.Date")) { 
			field.set(obj, rs.getDate(field.getName())); 
		} 
	} 
 
}

这个可以放在utils中，具体用法如下：

package com.liuxinquan.service; 
 
import java.util.List; 
 
import javax.annotation.Resource; 
 
import org.springframework.jdbc.core.JdbcTemplate; 
import org.springframework.stereotype.Service; 
 
import com.liuxinquan.entiry.Book; 
import com.liuxinquan.utils.CommonObj; 
 
/** 
 * @author: 
 @类说明： 
 *  
 */ 
@Service 
public class BookService { 
	@Resource(name = "jdbcTemplate") 
	public JdbcTemplate jdbcTemplate; 
 
	public List<Object> findAll() { 
		String sql = "select * from recommender_prefer "; 
		List<Object> books = jdbcTemplate.query(sql, new CommonObj(Book.class)); 
		return books; 
	} 
 
	public Object findbyId(String id) { 
		String sql = "select * from recommender_prefer where id =" + id; 
		Object book = jdbcTemplate.queryForObject(sql, new CommonObj(Book.class)); 
		return book; 
	} 
	 
}

service亦可以简化的，网上有很多，关于通用增删改查，自己可以搜一下。希望能有所帮助。