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。