主要使用后端验证，调用awt API ，会简单调用即可，绘图代码已封装到LoginVerifyUtils中。
界面展示：
LoginVerifyUtils全部代码
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random; import javax.imageio.ImageIO; public class LoginVerifyUtils { private static LoginVerifyUtils loginVerifyUtils = new LoginVerifyUtils(); private LoginVerifyUtils() {
} public static LoginVerifyUtils getInstance() {
return loginVerifyUtils;
} /**
* 绘画验证码
* @param output
* @return
*/
public String drawImg(ByteArrayOutputStream output) {
String code = "";
// 随机产生4个字符
for (int i = 0; i < 4; i++) {
code += randomChar();
}
int width = 70;
int height = 25;
BufferedImage bi = new BufferedImage(width, height,
BufferedImage.TYPE_3BYTE_BGR);
Font font = new Font("Times New Roman", Font.PLAIN, 20);
// 调用Graphics2D绘画验证码
Graphics2D g = bi.createGraphics();
g.setFont(font);
Color color = new Color(66, 2, 82);
g.setColor(color);
g.setBackground(new Color(226, 226, 240));
g.clearRect(0, 0, width, height);
FontRenderContext context = g.getFontRenderContext();
Rectangle2D bounds = font.getStringBounds(code, context);
double x = (width - bounds.getWidth()) / 2;
double y = (height - bounds.getHeight()) / 2;
double ascent = bounds.getY();
double baseY = y - ascent;
g.drawString(code, (int) x, (int) baseY);
g.dispose();
try {
ImageIO.write(bi, "jpg", output);
} catch (IOException e) {
e.printStackTrace();
}
return code;
} /**
* 随机获取一个字符
* @return
*/
public char randomChar() {
Random r = new Random();
String s = "ABCDEFGHJKLMNPRSTUVWXYZ0123456789";
return s.charAt(r.nextInt(s.length()));
}
}
login.jsp
<div id="login">
<div class="form-inline" > <div class="input-group">
<span class="input-group-addon">账号</span>
<input type="text" class="form-control" name="id" id="adminId">
</div><br/><br/> <div class="input-group">
<span class="input-group-addon">密码</span>
<input type="password" class="form-control" name="passwd" id="passwd">
</div> <br/><br/>
<div class="input-group">
<span class="code_img"> <img
src="${APP_PATH}/admin/getVerifyCode"
width="110" height="40" id="verifyCodeImage"> </span><a id="changeVerifImageRegister"
onclick="javascript:changeImage();">换一张</a>
</div> <br/><br/>
<div class="input-group">
<span class="input-group-addon">验证码</span>
<input type="text" class="form-control" name="verifyCode" style="width: 184px" id="verifyCode">
</div><br/> <p style="text-align: right;color: red;position: absolute" id="info"></p> <br/>
<button id="loginButton" class="btn btn-primary">登陆
</button> </div>
依赖ui库
<link rel="stylesheet" href="${APP_PATH }/static/css/bootstrap.min.css">
<script src="${APP_PATH }/static/js/jquery-3.2.1.min.js"></script>
<script src="${APP_PATH }/static/js/bootstrap.min.js"></script>javascript
$("#loginButton").click(function () {
if($("#adminId").val()==''&&$("#passwd").val()==''){
$("#info").text("提示:账号和密码不能为空");
}
else if ($("#adminId").val()==''){
$("#info").text("提示:账号不能为空");
}
else if($("#passwd").val()==''){
$("#info").text("提示:密码不能为空");
}else if($("#verifyCode").val()==''){
$("#info").text("提示:请输入验证码");
}
else {
//验证码
$.ajax({
type: "GET",
url: "${APP_PATH}/admin/verifyCode",
data: {
verifyCode:$("#verifyCode").val() ,
},
dataType: "json",
success: function(data) {
if(data.stateCode.trim() == "1003") {
$("#info").text("提示:服务器异常");
flag = false;
} else if(data.stateCode.trim() == "1002") {
$("#info").text("提示:验证码错误");
} else{
userLogin()
}
}
});
}
})
function userLogin(){
$.ajax({
type: "POST",
url: "${APP_PATH}/admin/login",
data: {
username:$("#adminId").val() ,
password: $("#passwd").val()
},
dataType: "json",
success: function(data) {
if(data.stateCode.trim() == "1003") {
$("#info").text("提示:该用户不存在");
} else if(data.stateCode.trim() == "1002") {
$("#info").text("提示:密码错误");
} else if(data.stateCode.trim() == "1001"){
$("#info").text("提示:登陆成功，跳转中...");
window.location.href="${APP_PATH}/main";
}else{
$("#info").text("提示:服务器出错");
}
}
});
}loginController参考
/**
* 获取验证码
* @param response
* @param session
*/
@GetMapping("/getVerifyCode")
public void generate(HttpServletResponse response, HttpSession session) { ByteArrayOutputStream output = new ByteArrayOutputStream(); LoginVerifyUtils loginVerifyUtils = LoginVerifyUtils.getInstance();
String verifyCodeValue =loginVerifyUtils.drawImg(output); session.setAttribute("verifyCodeValue", verifyCodeValue); try {
ServletOutputStream out = response.getOutputStream();
output.writeTo(out);
} catch (IOException e) {
e.printStackTrace();
} } //验证
@GetMapping("/verifyCode")
public @ResponseBody AJAXResult verifyCode(@RequestParam("verifyCode") String verifyCode ,HttpSession session) {
AJAXResult result = new AJAXResult();
try {
String verifyCodeValue = (String) session.getAttribute("verifyCodeValue");
if(verifyCode.trim().toUpperCase().equals(verifyCodeValue)) {
result.setStateCode("1001");
}
} catch (Exception e) {
e.printStackTrace();
result.setStateCode("1003");
}
return result;
} @ResponseBody
@PostMapping("/login")
public Object login(Admin admin ,HttpServletRequest request) {
AJAXResult result = new AJAXResult();
try {
Wrapper<Admin> wrapper = new EntityWrapper<Admin>();
wrapper.eq("username", admin.getUsername());
boolean isName = adminService.selectOne(wrapper) == null ? true: false;
if(isName) {
result.setStateCode("1003");//用户名不存在
}else {
Wrapper<Admin> wrapper2 = new EntityWrapper<Admin>();
wrapper2.eq("username", admin.getUsername());
wrapper2.eq("password", admin.getPassword());
Admin loginAdmin = adminService.selectOne(wrapper2);
if(loginAdmin != null ) { request.getSession().setAttribute("loginAdmin", loginAdmin); LoginLog loginLog = new LoginLog();
loginLog.setAdminId(loginAdmin.getId());
loginLog.setLoginDate(new Date() );
loginLog.setLoginIp(request.getRemoteAddr());
loginLogService.insert(loginLog );
result.setStateCode( "1001");//登陆成功 }else {
result.setStateCode( "1002");//用户名或密码错误
}
}
} catch (Exception e) {
e.printStackTrace();
result.setStateCode( "1004");//服务器出错
}
return result ;
}
ps：主要逻辑就是把随机生成的验证码放到session域，当用户提交请求时，获取表单数据然后进行比对＜（＾－＾）＞
效果图
提供的代码尽量以参考为主，如有疑问，欢迎提出