Assertion.java
package com.test;
public class Assertion {
public static boolean isassert = true;
private static void printStack(String why) {
Throwable t = new Throwable(why);
t.printStackTrace();
System.exit(1);
}
public static void assert1(boolean expression, String why) {
if (isassert && !expression) {
printStack(why);
}
}
}
LoaderAssertions.java
package com.test;
public class LoaderAssertions {
public static void main(String[] args) {
ClassLoader loader= ClassLoader.getSystemClassLoader();
loader.setDefaultAssertionStatus(true);
new Loaded().go();
}
}
class Loaded {
public void go() {
assert false: "Testing";
}
}
Test1.java
package com.test;
import java.io.IOException;
public class Test1 {
int age1 = 11;
public static void main(String argv[]) throws IOException {
ClassLoader loader = ClassLoader.getSystemClassLoader();
loader.setDefaultAssertionStatus(true);
//loader.setClassAssertionStatus("com.test.Test1", true);
Test1 test=new Test1();
assert test.age1 >= 18 : "You are too young to vote";
}
}
Test2.java
package com.test;
import java.io.IOException;
public class Test2 {
public static void main(String argv[]) throws IOException {
int age1 =19;
assert age1 >=18:"You are too young to vote";
System.out.println("you are eligible to vote");
}
}
Showing posts with label java. Show all posts
Showing posts with label java. Show all posts
How to use cookies and how to get all request headers in servlets
CookieServlet.java
package com.rdta;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class CookieServlet extends HttpServlet {
/**Process the HTTP Get request*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Cookie c1 = new Cookie("userName", "prasanthi");
Cookie c2 = new Cookie("password", "sourav");
response.addCookie(c1);
response.addCookie(c2);
Cookie c3=new Cookie("santhi","test");
c3.setPath(request.getContextPath());
c3.setMaxAge(120);
response.addCookie(c3);
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Cookie Test</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("Please click the button to see the cookies sent to you.");
out.println("path"+c3.getPath());
out.println("path"+request.getContextPath());
out.println("<BR>");
out.println("<FORM METHOD=POST>");
out.println("<INPUT TYPE=SUBMIT VALUE=Submit>");
out.println("</FORM>");
out.println("</BODY>");
out.println("</HTML>");
}
/**Process the HTTP Post request*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException,IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Cookie Test</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<H2>Here are all the headers.</H2>");
Enumeration enum1 = request.getHeaderNames();
while (enum1.hasMoreElements()) {
String header = (String) enum1.nextElement();
out.print("<B>" + header + "</B>: ");
out.print(request.getHeader(header) + "<BR>");
}
out.println("<BR><BR><H2>And, here are all the cookies.</H2>");
Cookie[] cookies = request.getCookies();
int length = cookies.length;
for (int i=0; i<length; i++) {
Cookie cookie = cookies[i];
out.println("<B>Cookie Name:</B> " + cookie.getName() + "<BR>");
out.println("<B>Cookie Value:</B> " + cookie.getValue() + "<BR>");
}
out.println("</BODY>");
out.println("</HTML>");
}
}
cookie.html
<html>
<body>
<form method="get" action="cookie">
<input type="submit" value="submit"/>
</form>
</body>
</html>
web.xml
<web-app>
<servlet>
<servlet-name>cookie</servlet-name>
<servlet-class>com.rdta.CookieServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>cookie</servlet-name>
<url-pattern>/cookie</url-pattern>
</servlet-mapping>
</web-app>
package com.rdta;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class CookieServlet extends HttpServlet {
/**Process the HTTP Get request*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Cookie c1 = new Cookie("userName", "prasanthi");
Cookie c2 = new Cookie("password", "sourav");
response.addCookie(c1);
response.addCookie(c2);
Cookie c3=new Cookie("santhi","test");
c3.setPath(request.getContextPath());
c3.setMaxAge(120);
response.addCookie(c3);
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Cookie Test</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("Please click the button to see the cookies sent to you.");
out.println("path"+c3.getPath());
out.println("path"+request.getContextPath());
out.println("<BR>");
out.println("<FORM METHOD=POST>");
out.println("<INPUT TYPE=SUBMIT VALUE=Submit>");
out.println("</FORM>");
out.println("</BODY>");
out.println("</HTML>");
}
/**Process the HTTP Post request*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException,IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Cookie Test</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<H2>Here are all the headers.</H2>");
Enumeration enum1 = request.getHeaderNames();
while (enum1.hasMoreElements()) {
String header = (String) enum1.nextElement();
out.print("<B>" + header + "</B>: ");
out.print(request.getHeader(header) + "<BR>");
}
out.println("<BR><BR><H2>And, here are all the cookies.</H2>");
Cookie[] cookies = request.getCookies();
int length = cookies.length;
for (int i=0; i<length; i++) {
Cookie cookie = cookies[i];
out.println("<B>Cookie Name:</B> " + cookie.getName() + "<BR>");
out.println("<B>Cookie Value:</B> " + cookie.getValue() + "<BR>");
}
out.println("</BODY>");
out.println("</HTML>");
}
}
cookie.html
<html>
<body>
<form method="get" action="cookie">
<input type="submit" value="submit"/>
</form>
</body>
</html>
web.xml
<web-app>
<servlet>
<servlet-name>cookie</servlet-name>
<servlet-class>com.rdta.CookieServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>cookie</servlet-name>
<url-pattern>/cookie</url-pattern>
</servlet-mapping>
</web-app>
Cookie based Login in servlets
CookieLoginServlet
package com.rdta;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.sql.*;
public class CookieLoginServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
sendLoginForm(response, false);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String userName = request.getParameter("userName");
String password = request.getParameter("password");
if (login(userName, password)) {
Cookie c1 = new Cookie("userName", userName);
Cookie c2 = new Cookie("password", password);
response.addCookie(c1);
response.addCookie(c2);
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<META HTTP-EQUIV=Refresh CONTENT=0;URL=ContentServlet>");
}
else {
sendLoginForm(response, true);
}
}
private void sendLoginForm(HttpServletResponse response, boolean withErrorMessage)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Login</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<CENTER>");
if (withErrorMessage) {
out.println("Login failed. Please try again.<BR>");
}
out.println("<BR>");
out.println("<BR><H2>Login Page</H2>");
out.println("<BR>");
out.println("<BR>Please enter your user name and password.");
out.println("<BR>");
out.println("<BR><FORM METHOD=POST>");
out.println("<TABLE>");
out.println("<TR>");
out.println("<TD>User Name:</TD>");
out.println("<TD><INPUT TYPE=TEXT NAME=userName></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Password:</TD>");
out.println("<TD><INPUT TYPE=PASSWORD NAME=password></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD ALIGN=RIGHT COLSPAN=2>");
out.println("<INPUT TYPE=SUBMIT VALUE=Login></TD>");
out.println("</TR>");
out.println("</TABLE>");
out.println("</FORM>");
out.println("</CENTER>");
out.println("</BODY>");
out.println("</HTML>");
}
public static boolean login(String userName, String password) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/db2","root","indian");
Statement st = con.createStatement();
String sql = "SELECT name FROM login WHERE name='" +userName+ "' AND pwd='" + password + "'";
ResultSet rs = st.executeQuery(sql);
if (rs.next()) {
rs.close();
st.close();
con.close();
return true;
}
rs.close();
st.close();
con.close();
}
catch (ClassNotFoundException e) {
System.out.println(e.toString());
}
catch (SQLException e) {
System.out.println(e.toString());
}
catch (Exception e) {
System.out.println(e.toString());
}
return false;
}
}
package com.rdta;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.sql.*;
public class CookieLoginServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
sendLoginForm(response, false);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String userName = request.getParameter("userName");
String password = request.getParameter("password");
if (login(userName, password)) {
Cookie c1 = new Cookie("userName", userName);
Cookie c2 = new Cookie("password", password);
response.addCookie(c1);
response.addCookie(c2);
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<META HTTP-EQUIV=Refresh CONTENT=0;URL=ContentServlet>");
}
else {
sendLoginForm(response, true);
}
}
private void sendLoginForm(HttpServletResponse response, boolean withErrorMessage)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Login</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<CENTER>");
if (withErrorMessage) {
out.println("Login failed. Please try again.<BR>");
}
out.println("<BR>");
out.println("<BR><H2>Login Page</H2>");
out.println("<BR>");
out.println("<BR>Please enter your user name and password.");
out.println("<BR>");
out.println("<BR><FORM METHOD=POST>");
out.println("<TABLE>");
out.println("<TR>");
out.println("<TD>User Name:</TD>");
out.println("<TD><INPUT TYPE=TEXT NAME=userName></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Password:</TD>");
out.println("<TD><INPUT TYPE=PASSWORD NAME=password></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD ALIGN=RIGHT COLSPAN=2>");
out.println("<INPUT TYPE=SUBMIT VALUE=Login></TD>");
out.println("</TR>");
out.println("</TABLE>");
out.println("</FORM>");
out.println("</CENTER>");
out.println("</BODY>");
out.println("</HTML>");
}
public static boolean login(String userName, String password) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/db2","root","indian");
Statement st = con.createStatement();
String sql = "SELECT name FROM login WHERE name='" +userName+ "' AND pwd='" + password + "'";
ResultSet rs = st.executeQuery(sql);
if (rs.next()) {
rs.close();
st.close();
con.close();
return true;
}
rs.close();
st.close();
con.close();
}
catch (ClassNotFoundException e) {
System.out.println(e.toString());
}
catch (SQLException e) {
System.out.println(e.toString());
}
catch (Exception e) {
System.out.println(e.toString());
}
return false;
}
}
Ananomous Interface Example in Java
InterAnanomous.java
package com.inner;
interface Ananomous1 {
public String test="hello";
public String test1="hello test1";
void test();
void welcome();
}
public class InterAnanomous{
public static void main(String[] args) {
Ananomous1 ana=new Ananomous1(){
String test="anan hello";
public void test() {
System.out.println("hello test --- "+test);
}
public void welcome() {
System.out.println("welcomeeeeeeeee --- "+test1);
}
};
ana.welcome();
ana.test();
System.out.println("testsssss "+ana.test);
}
}
package com.inner;
interface Ananomous1 {
public String test="hello";
public String test1="hello test1";
void test();
void welcome();
}
public class InterAnanomous{
public static void main(String[] args) {
Ananomous1 ana=new Ananomous1(){
String test="anan hello";
public void test() {
System.out.println("hello test --- "+test);
}
public void welcome() {
System.out.println("welcomeeeeeeeee --- "+test1);
}
};
ana.welcome();
ana.test();
System.out.println("testsssss "+ana.test);
}
}
Method Ananomous Class Example in Java
MethodAnanomous.java
package com.inner;
interface Test{
public String hello="testing";
void see();
void look();
}
class Test1{
public void welcome(Test tr){
System.out.println("test ttttttt "+tr.hello);
tr.see();
}
}
public class MethodAnanomous {
public static void main(String[] args) {
Test1 met=new Test1();
met.welcome(
new Test(){
public String hello="rterterteresting";
public void look() {
System.out.println("hhjhhhh");
}
public void see() {
System.out.println("seeeeeeee "+hello);
}
}
);
}
}
Ananomous Class Example in Java
Ananomous.java
package com.inner;
public String ss="ter";
void ert(){
String ss="ter";
System.out.println("1111 "+ss);
void test()
{
System.out.println("2222 "+this.ss);
}
Ananomous ana=new Ananomous(){
public String ss="an2";
void ert(){
String ss="an1";
System.out.println("aaa 1111 "+ss);
System.out.println("aaa 222 "+this.ss);
}
ana.test();
ana.ert();
System.out.println("rrrrrrrrrr "+ana.ss);
}
MethodInner Class Example in Java
MethodOuter.java
package com.inner;
public class MethodOuter {
private String ii="rter";
public void test()
{
final String ii ="ree";
class MethodInner{
private String ss="tet";
private void test()
{
System.out.println("11111 "+ss);
System.out.println("222222 "+MethodOuter.this.ii);
System.out.println("3333 "+ii);
}
}
MethodInner mm=new MethodInner();
mm.test();
System.out.println("typeeeeeeeeee"+ii);
}
public static void main(String[] args) {
MethodOuter met=new MethodOuter();
met.test();
}
}
package com.inner;
public class MethodOuter {
private String ii="rter";
public void test()
{
final String ii ="ree";
class MethodInner{
private String ss="tet";
private void test()
{
System.out.println("11111 "+ss);
System.out.println("222222 "+MethodOuter.this.ii);
System.out.println("3333 "+ii);
}
}
MethodInner mm=new MethodInner();
mm.test();
System.out.println("typeeeeeeeeee"+ii);
}
public static void main(String[] args) {
MethodOuter met=new MethodOuter();
met.test();
}
}
Static Inner Class Example in java
StaticOuter.java
package com.inner;
public class StaticOuter {
private String s="tt";
private static String y="yr";
static class StaticInner{
private String s="tt";
private static String y="ff";
void test()
{
System.out.println("1111 "+s);
System.out.println("22222 "+y);
System.out.println("33333 "+StaticOuter.y);
}
}
}
StaticTestOuter.java
package com.inner;
public class StaticTestOuter {
public static void main(String[] args) {
StaticOuter.StaticInner ss=new StaticOuter.StaticInner();
ss.test();
}
}
Inner Class Example in Java
outer.java
package com.inner;
public class Outer {
private String a="test";
class Inner{
private static final int i=8;
private String a="ss";
void test()
{
System.out.println("hello "+i);
System.out.println("outer test "+a);
System.out.println("string is "+this.a);
System.out.println("String in outer is "+Outer.this.a);
}
}
}
TestOuter.java
package com.inner;
public class TestOuter {
public static void main(String[] args) {
//Outer.Inner inn=new Outer().new Inner();
Outer out=new Outer();
Outer.Inner inn=out.new Inner();
inn.test();
}
}
package com.inner;
public class Outer {
private String a="test";
class Inner{
private static final int i=8;
private String a="ss";
void test()
{
System.out.println("hello "+i);
System.out.println("outer test "+a);
System.out.println("string is "+this.a);
System.out.println("String in outer is "+Outer.this.a);
}
}
}
TestOuter.java
package com.inner;
public class TestOuter {
public static void main(String[] args) {
//Outer.Inner inn=new Outer().new Inner();
Outer out=new Outer();
Outer.Inner inn=out.new Inner();
inn.test();
}
}
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