Mysql插入语句和传递参数给PHP

Question

我正在尝试在我的 PHP 文件中执行各种语句/查询，具体取决于接收到的变量（此外，有没有办法发送变量并选择我想要执行的查询类型，而不是进行一次查询对于收到的每组变量？这是我第一次用 PHP 编写，所以请原谅可能的愚蠢问题）。

在这种情况下，它是用户名、密码和用户 ID。我希望在收到这 3 个变量时进行插入。但是，我不断收到错误消息：java.net.ProtocolException：方法不支持请求正文：GET（这是 conn.setDoOutput 设置为 true 时）。如果我将其设置为 false，我会收到一个 IO URL 错误，指出无法找到我的 URL。我究竟做错了什么？下面是我的 php 脚本和用于 GET 请求的 java 代码。

<?php
$con=mysqli_connect("logindetailsgohere");

if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

if (isset($_GET['Username']) && isset($_Get['Password']) && isset($_GET['UserID'])){
$uname = mysql_real_escape_string($_GET['Username']);
$pass = mysql_real_escape_string($_GET['Password']);
$uid = intval($_GET['UserID']);
$sql = "INSERT IGNORE INTO Users (id, Username, Password) VALUES ('$uid', '$uname', '$pass')";
if(mysqli_query($con, $sql){
    echo "Values have been inserted";
}
}

mysqli_close($con);
?>

Java 代码：

public String connect() {

    try {
        /*URL url = new URL("phpfilelocation.php");*/
        String data = URLEncoder.encode("un", "UTF-8") + "=" + URLEncoder.encode(un, "UTF-8");
        data += "&" + URLEncoder.encode("pw", "UTF-8") + "=" + URLEncoder.encode(pw, "UTF-8");
        data += "&" + URLEncoder.encode("uid", "UTF-8") + "=" + URLEncoder.encode(Integer.toString(uid), "UTF-8");

        URL url = new URL("phpfilelocation.php");
        URLConnection conn = url.openConnection();

        conn.setDoOutput(true);
        OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());

        wr.write(data);
        wr.flush();

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

        StringBuilder sb = new StringBuilder();
        String line = null;

        // Read Server Response
        while((line = reader.readLine()) != null)
        {
            sb.append(line);
            break;
        }
        return sb.toString();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return "fail";
}

Answer 1

由于此 PHP 脚本执行 INSERT 语句，因此强烈建议您使用 POST 参数。

Java 代码：

public String connect() {

    try {
    /*URL url = new URL("phpfilelocation.php");*/
        String data = "&" + URLEncoder.encode("un", "UTF-8") + "=" + URLEncoder.encode(un, "UTF-8");
        data += "&" + URLEncoder.encode("pw", "UTF-8") + "=" + URLEncoder.encode(pw, "UTF-8");
        data += "&" + URLEncoder.encode("uid", "UTF-8") + "=" + URLEncoder.encode(Integer.toString(uid), "UTF-8");

        URL url = new URL("phpfilelocation.php");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        conn.setDoOutput(true);
        conn.setRequestMethod("POST");
        conn.connect();

        OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
        wr.write(data);
        wr.flush();

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

        StringBuilder sb = new StringBuilder();
        String line = null;

        // Read Server Response
        while((line = reader.readLine()) != null)
        {
            sb.append(line);
            break;
        }
        return sb.toString();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return "fail";
}

PHP 脚本：

<?php
$con=mysqli_connect("logindetailsgohere");

if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

if (isset($_POST['un']) && isset($_POST['pw']) && isset($_POST['uid'])){
$uname = mysql_real_escape_string($_POST['un']);
$pass = mysql_real_escape_string($_POST['pw']);
$uid = intval($_POST['uid']);
$sql = "INSERT IGNORE INTO Users (id, Username, Password) VALUES ('$uid', '$uname', '$pass')";
if(mysqli_query($con, $sql){
    echo "Values have been inserted";
}
}

mysqli_close($con);
?>

顺便说一句，对于 GET 请求，您只需在创建 URL 对象时将参数附加到 url 的末尾。

public String connect() {

    try {
    /*URL url = new URL("phpfilelocation.php");*/
        String data = URLEncoder.encode("un", "UTF-8") + "=" + URLEncoder.encode(un, "UTF-8");
        data += "&" + URLEncoder.encode("pw", "UTF-8") + "=" + URLEncoder.encode(pw, "UTF-8");
        data += "&" + URLEncoder.encode("uid", "UTF-8") + "=" + URLEncoder.encode(Integer.toString(uid), "UTF-8");

        String urlString = "phpfilelocation.php" + "?" + data;
        URL url = new URL(urlString);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        conn.setDoOutput(false);
        conn.setRequestMethod("GET");
        conn.connect();

        //remove:
        //OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
        //wr.write(data);
        //wr.flush();

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

        StringBuilder sb = new StringBuilder();
        String line = null;

        // Read Server Response
        while((line = reader.readLine()) != null)
        {
            sb.append(line);
            break;
        }
        return sb.toString();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return "fail";
}

Answer 2

PHP：

mysql_query("INSERT INTO Users(id, UserName, Password)
VALUES ('$uid', '$uname', '$pass')");

JAVA：

String driver="com.mysql.jdbc.Driver";
String url="jdbc:mysql://localhost:3306/dbname";
String unameDB="username";
String passDB="password";
Class.forName(driver);
Connection c=(Connection) DriverManager.getConnection(url,unameDB,passDB);
Statement s=c.createStatement();
s.executeUpdate("INSERT INTO `Users`(ID,UserName,Password) VALUE ('"+uid+"','"+uname+"','"+pass+"')");