java - 如何从 SQL 查询中提取列名作为字符串 SQL 查询作为字符串传递

Question

SQL 查询将作为字符串传递给我的方法，如果查询是例如，我如何检索查询中的列名

Select name, dob, age, gender from table1; or 
Select uname AS name, hgt AS height, wgt AS weight from table1;

我想获取数组或列表中的列名。

Answer 1

虽然有点令人费解，但这对问题中列出的两个查询都有效：

String query = "Select uname AS name, hgt AS height, wgt AS weight from table1";
Pattern p = Pattern.compile("\\s*\\w+,");Pattern p1 = Pattern.compile("\\s+\\w+\\s+from");
Matcher m = p.matcher(query);Matcher m1=p1.matcher(query);
String colsOnly="";
while(m.find()){colsOnly+=(m.group().trim());}
while(m1.find()){colsOnly+=(m1.group().substring(0,m1.group().length()-4).trim());}
String[] cols = colsOnly.split(",");

Answer 2

你有没有尝试过

ResultSetMetaData rsmd = rs.getMetaData();
String name = rsmd.getColumnName(1);

Answer 3

    String str = "select dept,empid as eid , ename as name,deptname,deptid as department_id from emp";

    String[] arr = str.split("as");
    StringTokenizer str1 = new StringTokenizer(str, " ,");
    ArrayList<String> arrStr = new ArrayList<>();
    while (str1.hasMoreTokens())
    {
        String strT = str1.nextToken().toString();          
        arrStr.add(strT);
    }       
    for (int i = 0; i < arrStr.size(); i++)
    {
        if (arrStr.get(i).equals("as"))
        {
            System.out.println("Orignal\t" + arrStr.get(i - 1));
            System.out.println("Alias\t" + arrStr.get(i + 1));
        }
    }

输出

原始帝国

别名 eid

原名

别名

原始部门

别名部门_id