先在xml中配置bean
转发与重定向时可少些地址
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/"/>
<property name="suffix" value=".jsp"/>
</bean>
Controller中的方法的参数可以写什么?
例:
@RequestMapping("/list1")
@ResponseBody
public String list1(HttpServletRequest req){
// 需要什么对象在方法的参数中直接声明即可
// 从请求头中获取数据
String contentType = req.getHeader("Content-Type");
// 获取Session
// 如果仅需要Session, 那么可以在参数中直接声明
HttpSession session = req.getSession();
//转发到list1.jsp
return "list1";
}
验证码:
先创建验证码的工具类
package com.lanou.demo.service;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random;
public class VerifyCodeUtils {
//使用到Algerian字体，系统里没有的话需要安装字体，
// 字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
private static Random random = new Random();
/**
* 验证码对象
* @author zhou-baicheng
*
*/
public static class Verify{
private String code;//如 1 + 2
private Integer value;//如 3
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public Integer getValue() {
return value;
}
public void setValue(Integer value) {
this.value = value;
}
}
/**
* 使用系统默认字符源生成验证码
* @return
*/
public static Verify generateVerify(){
int number1 = new Random().nextInt(10) + 1;;
int number2 = new Random().nextInt(10) + 1;;
Verify entity = new Verify();
entity.setCode(number1 + " x " + number2);
entity.setValue(number1 + number2);
return entity;
}
/**
* 使用系统默认字符源生成验证码
* @param verifySize 验证码长度
* @return
*/
public static String generateVerifyCode(int verifySize){
return generateVerifyCode(verifySize, VERIFY_CODES);
}
/**
* 使用指定源生成验证码
* @param verifySize 验证码长度
* @param sources 验证码字符源
* @return
*/
public static String generateVerifyCode(int verifySize, String sources){
if(sources == null || sources.length() == 0){
sources = VERIFY_CODES;
}
int codesLen = sources.length();
Random rand = new Random(System.currentTimeMillis());
StringBuilder verifyCode = new StringBuilder(verifySize);
for(int i = 0; i < verifySize; i++){
verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));
}
return verifyCode.toString();
}
/**
* 生成随机验证码文件,并返回验证码值
* @param w
* @param h
* @param outputFile
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, outputFile, verifyCode);
return verifyCode;
}
/**
* 输出随机验证码图片流,并返回验证码值
* @param w
* @param h
* @param os
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, os, verifyCode);
return verifyCode;
}
/**
* 生成指定验证码图像文件
* @param w
* @param h
* @param outputFile
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, File outputFile, String code) throws IOException{
if(outputFile == null){
return;
}
File dir = outputFile.getParentFile();
if(!dir.exists()){
dir.mkdirs();
}
try{
outputFile.createNewFile();
FileOutputStream fos = new FileOutputStream(outputFile);
outputImage(w, h, fos, code);
fos.close();
} catch(IOException e){
throw e;
}
}
/**
* 输出指定验证码图片流
* @param w
* @param h
* @param os
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{
int verifySize = code.length();
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,
Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
Color.PINK, Color.YELLOW };
float[] fractions = new float[colors.length];
for(int i = 0; i < colors.length; i++){
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions);
g2.setColor(Color.GRAY);// 设置边框色
g2.fillRect(0, 0, w, h);
Color c = getRandColor(200, 250);
g2.setColor(c);// 设置背景色
g2.fillRect(0, 2, w, h-4);
//绘制干扰线
Random random = new Random();
g2.setColor(getRandColor(160, 200));// 设置线条的颜色
for (int i = 0; i < 20; i++) {
int x = random.nextInt(w - 1);
int y = random.nextInt(h - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g2.drawLine(x, y, x + xl + 40, y + yl + 20);
}
// 添加噪点
float yawpRate = 0.05f;// 噪声率
int area = (int) (yawpRate * w * h);
for (int i = 0; i < area; i++) {
int x = random.nextInt(w);
int y = random.nextInt(h);
int rgb = getRandomIntColor();
image.setRGB(x, y, rgb);
}
shear(g2, w, h, c);// 使图片扭曲
g2.setColor(getRandColor(100, 160));
int fontSize = h-4;
Font font = new Font("Algerian", Font.ITALIC, fontSize);
g2.setFont(font);
char[] chars = code.toCharArray();
for(int i = 0; i < verifySize; i++){
AffineTransform affine = new AffineTransform();
affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);
g2.setTransform(affine);
g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);
}
g2.dispose();
ImageIO.write(image, "jpg", os);
}
private static Color getRandColor(int fc, int bc) {
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
private static int getRandomIntColor() {
int[] rgb = getRandomRgb();
int color = 0;
for (int c : rgb) {
color = color << 8;
color = color | c;
}
return color;
}
private static int[] getRandomRgb() {
int[] rgb = new int[3];
for (int i = 0; i < 3; i++) {
rgb[i] = random.nextInt(255);
}
return rgb;
}
private static void shear(Graphics g, int w1, int h1, Color color) {
shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
}
private static void shearX(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(2);
boolean borderGap = true;
int frames = 1;
int phase = random.nextInt(2);
for (int i = 0; i < h1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
}
}
private static void shearY(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(40) + 10; // 50;
boolean borderGap = true;
int frames = 20;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
}
}
}
public static void main(String[] args) throws IOException{
File dir = new File("F:/verifies");
int w = 200, h = 80;
for(int i = 0; i < 50; i++){
String verifyCode = generateVerifyCode(4);
File file = new File(dir, verifyCode + ".jpg");
outputImage(w, h, file, verifyCode);
}
}
}
在创建一个实现View接口的实现类
在实现类中重写View接口的方法
package com.lanou.demo.service;
import org.springframework.web.servlet.View;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.util.Map;
public class VerifyCodeView implements View {
@Override
public String getContentType() {
return "image/png";
}
@Override
public void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) throws Exception {
//获取输出流
ServletOutputStream out = response.getOutputStream();
//从model中取出验证码
Object code = model.get("code");
//定义验证码
VerifyCodeUtils.outputImage(500, 100, out, String.valueOf(code));
}
}
方法的返回值
一般情况下常用的返回值类型有三种
1. String类型: 表示返回一个html模板
如果返回值是String类型, 那么会执行视图解析器
2. 返回集合/对象/Map, 配合@ResponseBody一起使用, 表示返回json
3. 返回ModelAndView对象
默认的html或json视图满足不了需求的情况下, 会自定义返回的视图
//view的用法
@RequestMapping("/category/view")
public ModelAndView findView(HttpSession session){
//创建ModelAndView对象
ModelAndView mv = new ModelAndView();
//调取验证码
String code = VerifyCodeUtils.generateVerifyCode(4);
//添加验证码到ModelAndView
mv.addObject("code", code);
//添加验证码加入session中
session.setAttribute("code", code);
//到实现类去添加视图
mv.setView(new VerifyCodeView());
返回模型和视图
return mv;
}
在前端显示时是:
<%--
Created by IntelliJ IDEA.
User: Risky57
Date: 2019/5/21
Time: 9:52
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>登录页面</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.js"></script>
</head>
<body>
<form action="/login.ex" method="post">
<input type="text" name="username">
<input type="text" name="password">
<input type="text" name="code">
<input type="submit">
<%--调用地址/category/view 的模型与视图--%>
<img id="code" src="/category/view" alt="">
</form>
<script>
<%-- 获取验证码--%>
var code = $('#code');
//写点击事件,点击一下换一张验证码
code.click(function () {
code.attr('src', '/category/view?' + Math.random())
});
</script>
</body>
</html>
在后台对登录进行判断
@RequestMapping("/login")
public String doLogin(String username,
String password,
String code,
HttpSession session){
String sessionCode = (String) session.getAttribute("code");
if ("admin".equals(username) && "admin".equals(password)){
if (sessionCode.equalsIgnoreCase(code)){
// 验证过一次之后, 移除到验证码
session.removeAttribute("code");
//把用户名添加到session
session.setAttribute("user", "xxxxx");
//获取许可证
String[] permissions = {"one", "hello", "insert3"};
//把许可证添加到session
session.setAttribute("permissions", Arrays.asList(permissions));
// 重定向到/home页面
return "redirect:/home";
}
}
//如果不符合if判断就重定向到error页面
return "redirect:/error";
}
转发与重定向
重定向
return "redirect:/error";
转发:转发要写配置文件
//转发到list1.jsp
return "list1";
