日常错误整理

「爱情、让人受尽委屈。」 2022-03-18 10:06 248阅读 0赞

public void update(String tname,String hname,String titlevalue1,String titleid,int idvalue) {//改
    	//update ztetitle set title='solutions123' where titleid='1';
            String sql="update "+tname+" set "+hname+" = ? where "+" titleid ="+idvalue+"";
    		try {
    			database.conn=database.getConn();
    			database.pstm=database.conn.prepareStatement(sql);
    			database.pstm.setString(1, titlevalue1);//不知为什么hname必须用问号在下面set
    			database.pstm.executeUpdate();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}

public void update(String cloumn1,String title,String cloumnid,int id) {//改   
    		                  //  项目           title下目录
    	//update ztetitle set title='solutions123' where titleid='1;
            String sql="update ztetitle set "+cloumn1+" = ? where ? = ?";//set后面直接代入列名，列值则用？导入
    		try {
    			database.conn=database.getConn();
    			database.pstm=database.conn.prepareStatement(sql);
    			database.pstm.setString(1,title);
    			database.pstm.setString(2,cloumnid );
    			database.pstm.setString(3,(id+""));
    			database.pstm.executeUpdate();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		database.close();
    	}

两句关于datetime的sql
    select n.newsname,(to_number(to_char(n.NEWSDATE,'yyyymmdd'))),p.explaination from news n,picture p where n.news_id =p.id and n.news_id=#{newsId}
     insert into news values (#{newsName},to_date(#{newsDate},'yyyymmdd'),#{newsId})//在xml中千万不能有分号

mybaits错误解决：There is no getter for property named ... in 'class java.lang.String'
    <select id = "getNewsById" parameterType = "int" resultMap = "news">
            select *
            from News
            where newsid in
            <foreach collection ="#{_parameter}" item = "item" index = "index"//此处用#{_parameter}或者接口加@Param("newsId")
                     open = "(" separator = "," close = " )">
                     //Could not set parameters for mapping把#改成$
                     ${item}
            </foreach>
        </select>

关于property,里面换行不要打冒号不要打冒号不要打冒号