springmvc工具类封装RowMapper (未测试)

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(tr
4000
ue);
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。

 

SpringMVC

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fishing
2016-02-18 15:49 代码数：0

只有搞有时候可能会出问题，

如：不是查询所有字段时，查询的返回结果中没有field的名称时 （ rs.getString(field.getName())); ）

就会报异常