package com.blog.db.dao;

import com.blog.util.Pagination;

import java.util.List;

public interface PublicDao<T> {

    public void setMapper(Class t);

    public void setTableName(String tn);

    public List<T> queryList(Pagination pagination);

    public void deleteByID(int ID);

    public void add(T t,Object[] values,int[] types);

    public T queryById(int id);

    public T queryByField(String fieldname,String value);

    public void updateByID(T t,int ID,Object[] values,int[] types);

}

package com.blog.db.dao.impl;

import com.blog.db.dao.PublicDao;

import com.blog.util.Pagination;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.dao.EmptyResultDataAccessException;

import org.springframework.jdbc.core.BeanPropertyRowMapper;

import org.springframework.jdbc.core.JdbcTemplate;

import org.springframework.jdbc.core.RowMapper;

import org.springframework.stereotype.Repository;

import javax.annotation.Resource;

import java.sql.Types;

import java.util.List;

/**

 * 公共dao实现

 * @deprecated  提供常见的列表、插入、查询单个、更新数据服务

 * @author ztf

 * */

@Repository("publicDao")

public class PublicDaoimpl<T> implements PublicDao<T> {

    @Resource

    private JdbcTemplate jdbcTemplate;

    private String table_name = ""; //表名称

    private List<String> fields; //表字段

    @Value("${db_schema}")

    private String schema; //表模式

    private RowMapper<T> mapper;

    /**

     * 设置Mapper映射

     */

    public void setMapper(Class t){

        this.mapper = new BeanPropertyRowMapper<T>(t);

    }

    public RowMapper<T> getMapper(){

        return mapper;

    }

    public void setTableName(String tn){

        this.table_name = tn;

    }

    public String getTable_name() {

        return schema+"."+table_name;

    }

    public List<String> getFields(){

        return this.fields;

    }

    public String getFieldsToString(){

        String _fields;

        List<String> fields = getFields();

        _fields = String.join(",",fields);

        return _fields;

    }

    /**

     *  查询列表

     *  @param pagination 传入公共util中定义的分页对象

     *  @return List<T>

     * */

    public List<T> queryList(Pagination pagination) {

        List lists = null;

        String sql = "select * from ? ?";

        lists = jdbcTemplate.queryForList(

                sql,

                getTable_name(),

                pagination.getSql(),

                getMapper()

        );

        return lists;

    }

    /**

     *  根据ID删除某一个行

     *  @param ID 传入行id

     * */

    public void deleteByID(int ID) {

        String sql = "delete from "+

                getTable_name()+" where ID=?";

        jdbcTemplate.update(

                sql,

                new Object[] { ID },

                new int[] {Types.INTEGER}

        );

    }

    /**

     *  插入数据

     *  @param t 传入操作的数据对象

     *  @param values 值的object[]对象

     *  @param types 值对象的类型

     * */

    public void add(T t,Object[] values,int[] types) {

        String sql = "insert into "+getTable_name()+"("+getFieldsToString()+") values(?)";

        jdbcTemplate.update(

                sql,

                values,

                types

        );

    }

    /**

     *  根据ID查询指定的行

     *  @param id 传入id

     * */

    public T queryById(int id) {

        T t = null;

        String sql = "select * from "+getTable_name()+" where ID=?";

        try{

            t = jdbcTemplate.queryForObject(

                    sql,

                    new Object[] {id},

                    new int[] {Types.INTEGER},

                    getMapper()

            );

        }catch(EmptyResultDataAccessException e){

            t = null;

        }

        return t;

    }

    /**

     *  根据指定的fieldname查询指定值的单行数据

     *  @param fieldname 传入id

     * */

    public T queryByField(String fieldname,String value) {

        T t = null;

        String sql = "select * from "+getTable_name()+" where "+fieldname+"=?";

        try{

            t = jdbcTemplate.queryForObject(

                    sql,

                    new Object[] {value},

                    new int[] {Types.VARCHAR},

                    getMapper()

            );

        }catch(EmptyResultDataAccessException e){

            t = null;

        }

        return t;

    }

    /**

     *  根据指定的id更新指定值的单行数据

     *  @param t 传入更新对象

     *  @param ID 传入指定的ID

     *  @param values 值的object[]对象

     *  @param types 值对象的类型 int[]

     * */

    public void updateByID(T t, int ID,Object[] values,int[] types) {

        String sql = "update "+getTable_name()+" set username=?,password=?,pic=?,describe=?,check_time=? where ID="+ID;

        jdbcTemplate.update(

                sql,

                values,

                types

        );

    }

}

private RowMapper<T> mapper;

    /**

     * 设置Mapper映射

     */

    public void setMapper(Class t){

        this.mapper = new BeanPropertyRowMapper<T>(t);

    }

    public RowMapper<T> getMapper(){

        return mapper;

    }

 @Qualifier("publicDao")

    private PublicDao<User> ud;

    public User Sign(String username, String password) throws UnsupportedEncodingException {

        String md5_pass = MD5Encryption.getEncryption(password);

        ud.setTableName("users"); //指定查询表名

        ud.setMapper(User.class); //指定映射class对象

        User user = ud.queryByField("username",username); //根据字段 username查询值为xxx