web阶段学习体验感

1) web阶段学的东西多而杂,要学会分类,思路清晰了是第一步,用的时候再去查相应的文档.2) 需要细心,有很多用的到字符串拼接的地方,一不小心就会拼错,到时候会报sql语法错误如下代码:

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?

@Override

public List<Route> findByPage(int cid, int start, int pageSize,String rname) {

//

// String sql = "select * from tab_route where cid = ? limit ? , ?";

//

// return jtl.query(sql,new BeanPropertyRowMapper<Route>(Route.class),cid,start,pageSize);

String sql = "select * from tab_route where 1=1";

StringBuilder sb = new StringBuilder(sql);

ArrayList arr = new ArrayList<>();

if (cid != 0) {

sb.append(" and cid = ? ");

arr.add(cid);//添加？对应的值

}

if (rname != null && rname.length() > 0&& !"null".equals(rname)) {

sb.append(" and rname like ?");

arr.add("%" + rname + "%");

}

arr.add(start);

arr.add(pageSize);

sb.append(" limit ? , ? ");

sql = sb.toString();

return jtl.query(sql, new BeanPropertyRowMapper<Route>(Route.class), arr.toArray());

}