參數索引超出范圍（8>參數數量，即7）

Question

我有此數據庫表：

create table users(
    id int not null auto_increment,
    fn varchar(30),
    ln varchar(30),
    sex char,
    email varchar(60),
    country varchar(40),
    username varchar(30),
    password varchar(100),
    primary key(id)
);

運行此代碼時，出現錯誤：參數索引超出范圍（8>參數數量，即7）。 我也嘗試更改setString(1,fn)但是它不起作用。

 try{
     String INSERT="INSERT INTO users (fn,ln,,sex,email,country,username,password) VALUES (?,?,?,?,?,?,?)";
     PreparedStatement pst=conn.prepareStatement(INSERT);
     System.out.println("Created prepared statement");

     pst.setString(2,"fn");
     pst.setString(3,"ln");
     pst.setString(4,"sex");
     pst.setString(5,"email");
     pst.setString(6,"country");
     pst.setString(7,"username");
     pst.setString(8,"password)");
     pst.executeUpdate();
 }

Answer 1

您的查詢中有一個逗號，並且列數應從1開始。

String INSERT="INSERT INTO users (fn,ln,sex,email,country,username,password) VALUES (?,?,?,?,?,?,?)";
pst.setString(1,"fn");
    pst.setString(2,"ln");
    pst.setString(3,"sex");
    pst.setString(4,"email");
    pst.setString(5,"country");
    pst.setString(6,"username");
    pst.setString(7,"password)");
    pst.executeUpdate();

Answer 2

您正在傳遞8列和7個變量，計數不匹配。

確保是否：

String INSERT="INSERT INTO users (fn,ln,,sex,email,country,username,password) VALUES (?,?,?,?,?,?,?)";

應該是這樣的：

String INSERT="INSERT INTO users (fn,ln,sex,email,country,username,password) VALUES (?,?,?,?,?,?,?)";

Answer 3

相對於查詢的參數號

pst.setString(1,"fn");
pst.setString(2,"ln");
pst.setString(3,"sex");
pst.setString(4,"email");
pst.setString(5,"country");
pst.setString(6,"username");
pst.setString(7,"password)");
pst.executeUpdate();

Answer 4

更正：

String INSERT="INSERT INTO users (fn,ln,sex,email,country,username,password) VALUES (?,?,?,?,?,?,?)";

和

short c = 0;
    //using a counter variable (short or int) means
    //no worries about numbering - just maintain the order below
pst.setString(++c,"fn");
pst.setString(++c,"ln");
pst.setString(++c,"sex");
pst.setString(++c,"email");
pst.setString(++c,"country");
pst.setString(++c,"username");
pst.setString(++c,"password)");

注意： ++c是預增量運算符。 它將c的當前值加c （為此設置c ）並使用c的新值。