jdbc 动态sql语句拼接 查询不出结果

Question

public List queryByCondition(String command, String description) {
// message列表
List messageList = new ArrayList();
try {
// 加载驱动
Class.forName("com.mysql.jdbc.Driver");
// 数据库的连接
Connection conn;
conn = DriverManager
.getConnection("jdbc:mysql://localhost:3306/micro_message",
"root", "root");
StringBuffer sql = new StringBuffer(
"select ID,COMMAND,DESCRIPTION,CONTENT from message where 1=1");
List paramList = new ArrayList();
if (command != null && !command.trim().equals("")) {
sql.append(" and COMMAND=?");
paramList.add(command);
}
if (description != null && !description.trim().equals("")) {
sql.append(" and DESCRIPTION='%' ? '%'");
paramList.add(description);
}
PreparedStatement pstmt = conn.prepareStatement(sql.toString());
for(int i=0;i<paramList.size();i++){
pstmt.setString(i+1, paramList.get(i));
}
System.out.println(sql);
ResultSet re = pstmt.executeQuery();
while (re.next()) {
Message message = new Message();
message.setId(re.getInt(1));
message.setCommand(re.getString(2));
message.setDescription(re.getString(3));
message.setContent(re.getString(4));
messageList.add(message);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return messageList;
}

Answer 1

报错吗……。。。。