Question

有人请帮助我。我正在做正确的事但我得到一个错误。它是一个链接到MYSQL wamp服务器的JAVA应用程序。

错误： com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException：您的SQL语法中有错误;检查与MySQL服务器版本对应的手册，以便在第1行的“Chege”附近使用正确的语法

我的代码：

public class MyQuery {

    public Connection getConnection() {
        Connection con = null;
        try {
            con = DriverManager.getConnection("jdbc:mysql://"
                    + "localhost:3306/employee_certificate", "root", "");
        } catch (SQLException ex) {
            Logger.getLogger(Query.class.getName())
                    .log(Level.SEVERE, null, ex);
        }
        return con;
    }

    public ArrayList<Item> getData(String EmpName) {
        ArrayList<Item> list = new ArrayList<Item>();
        Connection con = getConnection();
        Statement st;
        ResultSet rs;
        try {
            st = con.createStatement();
            rs = st.executeQuery("SELECT Emp_Id, Emp_Name, Department "
                    + "FROM staff WHERE Emp_Name = " + EmpName + " ");
            Item I;
            while (rs.next()) {
                I = new Item(
                        rs.getString("Emp_Id"),
                        rs.getString("Emp_Name"),
                        rs.getString("Department"));
                list.add(I);
            }
        } catch (SQLException ex) {
            Logger.getLogger(Query.class.getName()).log(Level.SEVERE, null, ex);
        }
        return list;
    }
}

Answer 1

您的查询字符串不正确。应该类似于以下内容：

rs=st.executeQuery("SELECT Emp_Id, Emp_Name, Department "
          + "FROM staff WHERE Emp_Name = '"+EmpName+"'");

但我建议使用PreparedStatement对象将SQL语句发送到数据库。

String query = "SELECT Emp_Id, Emp_Name, Department FROM staff WHERE Emp_Name = ?";
PreparedStatement preStatement = conn.prepareStatement(query);
preStatement.setString(1, EmpName);
ResultSet result = preStatement.executeQuery();

这种方法更安全，更方便。

Answer 2

您的查询中存在一些问题：

try {
    st = con.createStatement();
    //Add quotes 'YourString'
    rs = st.executeQuery("SELECT Emp_Id, Emp_Name, Department "
            + "FROM staff WHERE Emp_Name = '" + EmpName + "' ");
    Item I;
    while (rs.next()) {
        I = new Item(rs.getString("Emp_Id"), rs.getString("Emp_Name"), rs.getString("Department"));
        list.add(I);
    }
} catch (SQLException ex) {
    Logger.getLogger(Query.class.getName()).log(Level.SEVERE, null, ex);
}

或安全查询使用预备声明：

try {
    PreparedStatement ps = connection.prepareStatement("SELECT Emp_Id, Emp_Name, Department FROM staff WHERE Emp_Name = ?");
    ps.setString(1, EmpName);
    rs = ps.executeUpdate();
    Item I;
    while (rs.next()) {
        I = new Item(rs.getString("Emp_Id"), rs.getString("Emp_Name"), rs.getString("Department"));
        list.add(I);
    }
} catch (SQLException ex) {
    Logger.getLogger(Query.class.getName()).log(Level.SEVERE, null, ex);
}

JAVA中的MySQLSyntaxErrorException

2 个答案: