Java 为什么我的方法不接收布尔值?
我的servlet中有一个登录位Java 为什么我的方法不接收布尔值?,java,database,authentication,servlets,Java,Database,Authentication,Servlets,我的servlet中有一个登录位 else if (userPath.equals("/Login")) { String LuName = request.getParameter("LuserName"); String Lpass = request.getParameter("Lpassword"); boolean log = Boolean.parseBoolean(request.getParameter("loggedIn"));
else if (userPath.equals("/Login")) {
String LuName = request.getParameter("LuserName");
String Lpass = request.getParameter("Lpassword");
boolean log = Boolean.parseBoolean(request.getParameter("loggedIn"));
JavaSqlDb objDb2 = new JavaSqlDb("LineEquation");
objDb2.SelectDataReturn(LuName, Lpass, log);
String myUrl = "Welcome" + ".jsp";
try {
// Redirect back to the new URL with new data. Sending request from servlet to JSP.
if (log == true) {
request.getRequestDispatcher(myUrl).forward(request, response);
}
else {
System.out.println("Ya goofed.");
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
一个查找它所获得的值的方法
public boolean SelectDataReturn(String LuserName, String Lpassword, boolean loggedIn) {
// Public boolean or void?
Statement s = null;
ResultSet rs = null;
String dbQuery = "SELECT * FROM Users WHERE userName = '" + LuserName + "' AND password = '" + Lpassword + "' ";
try {
s = this.dbConn.createStatement();
rs = s.executeQuery(dbQuery);
if (rs.next()) {
LuserName = rs.getString(1);
Lpassword = rs.getString(2);
//loggedIn = rs.getBoolean(3);
loggedIn = true;
System.out.println(dbQuery + "found.");
} else {
//LuserName = rs.getString(1);
//Lpassword = rs.getString(2);
loggedIn = false;
System.out.println(dbQuery + "not found.");
}
String connectionURL = "jdbc:mysql://localhost:3306/" + this.dbName;
this.dbConn = DriverManager.getConnection(connectionURL, "root", "mysql1");
Statement st = this.dbConn.createStatement();
st.executeQuery(dbQuery);
dbConn.close();
} catch (SQLException se) {
System.out.println("SQL Error: Not able to find data.");
se.printStackTrace(System.err);
System.exit(0);
}
return loggedIn;
}
这是一个主要的方法
public static void main(String[] args) {
String tableName = "Users";
ArrayList<ArrayList<String>> myData;
String dbName = "LineEquation";
String[] tableHeader = {"userName", "password"};
JavaSqlDb objDb2 = new JavaSqlDb(dbName);
myData = objDb2.getData(tableName, tableHeader);
for (int row = 0; row < myData.size(); row++) {
System.out.println(myData.get(row));
}
objDb2.insertData("b", "2");
boolean test = objDb2.SelectDataReturn("Dhruv", "pass", false);
}
publicstaticvoidmain(字符串[]args){
String tableName=“用户”;
ArrayList myData;
字符串dbName=“LineEquation”;
字符串[]tableHeader={“用户名”,“密码”};
JavaSqlDb objDb2=新的JavaSqlDb(dbName);
myData=objDb2.getData(tableName,tableHeader);
对于(int row=0;row
我是servlet和数据库的相对初学者,因此您可以理解我为什么不理解,因为某种原因,当我在文本字段中输入值并提交它们时,会出现404错误和/或空白屏幕。我的servlet是否没有接收到布尔值或类似的内容,我是否要进入一个不存在的页面?布尔值是不可变的。如果您想以您希望在代码示例中使用的方式使用布尔值,则需要使用可变布尔值
在这篇文章中有一些选择 您正在为方法中的布尔参数指定一个新值,并希望调用方可以看到此更改。事实并非如此。Java使用。您应该删除布尔参数,而只返回true/false。