请问如何拼接sql语句，实现动态绑定sql

Question

想动态绑定sql，用java 写的sql语句如下：

id,name,dept_id 都是传进来的值.
sql = "select id,name,dept_id from users where 1=1 ";
if(id!=null &&id.equals(""))
sql += " and id = ?";
if(name!=null &&name.equals(""))
sql += " and name = ?";
if(dept_id !=null &&dept_id .equals(""))
sql += " and dept_id = ?";

pstmt = conn.prepareStatement(sql);
这个地方怎么写pstmt.set.........("","");
rs = pstmt.executeQuery();

我想拼接的每个循环里面"pstmt.setString("+i+",id");但是java不执行,还有什么别的方法或思路吗？

Answer 1

public void query(final Map map) throws Exception
{
StringBuffer sql = new StringBuffer("select id,name,dept_id from users where 1=1 ");

    for (final Entry<String, Object> entry : map.entrySet())
    {
        sql.append(", ").append(entry.getKey()).append("=?");
    }

    psmt = con.prepareStatement(sql.toString());

    int i = 0;

    for (final Entry<String, Object> entry : map.entrySet())
    {
        psmt.setObject(i, entry.getValue());
        i++;
    }
}