Question

Java大师，感谢您阅读我的问题。我会直言不讳。当我循环遍历数据库ResultSet对象并使用put方法更新LinkedHashMap时，所有先前添加的值都在更新。关键是Columnname和Value是给定列的属性列表。

        this.colpropmap=new LinkedHashMap<String, LinkedList<String>>();

        LinkedList<String> colproplist=new LinkedList<String>();

        while(crs.next()) {
            colproplist.clear();
            //Debug Statement
            //System.out.println(crs.getString("COLNAME") + " " + crs.getInt("COLNO"));
            colproplist.add(Integer.toString(crs.getInt("COLNO")));
            colproplist.add(crs.getString("DATATYPE"));
            //Debug Statement
            System.out.println("\t" + crs.getString("COLNAME") + ": " + colproplist);
            colpropmap.put(crs.getString("COLNAME"), colproplist);
            System.out.println("\t" + colpropmap);
        }

对于每次迭代，我看到所有以前的键都使用最新的Key值进行更新。有什么想法在这里发生了什么？

EMPID                         : [0, INTEGER(4,0)]
{EMPID                         =[0, INTEGER(4,0)]}
NAME                          : [1, VARCHAR(30,0)]
{EMPID                         =[1, VARCHAR(30,0)], NAME                         =[1, VARCHAR(30,0)]}
SALARY                        : [2, DECIMAL(5,2)]
{EMPID                         =[2, DECIMAL(5,2)], NAME                          =[2, DECIMAL(5,2)], SALARY                        =[2, DECIMAL(5,2)]}
EMPID                         : [0, INTEGER(4,0)]
{EMPID                         =[0, INTEGER(4,0)]}
NAME                          : [1, VARCHAR(25,0)]
{EMPID                         =[1, VARCHAR(25,0)], NAME                          =[1, VARCHAR(25,0)]}
SALARY                        : [2, DECIMAL(5,2)]
{EMPID                         =[2, DECIMAL(5,2)], NAME                          =[2, DECIMAL(5,2)], SALARY                        =[2, DECIMAL(5,2)]}

Java LinkedHashMap在更新单个密钥时更新所有值

0 个答案: