1.代码示例
输出打印
// 实际的逻辑是在这里
PrintWriter out = response.getWriter();
out.println("<h1>" + message + "</h1>");
out.println("<h1>" + username + "</h1>");
out.println("<h1>" + url + "</h1>");
配置文件 web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0"
metadata-complete="true">
<context-param>
<param-name>url</param-name>
<param-value>jdc:mysql://localhost:3306/mybatis</param-value>
</context-param>
<!--session 配置 单位分钟-->
<session-config>
<session-timeout>1</session-timeout>
</session-config>
<!--注册servlet-->
<servlet>
<servlet-name>hellServlet</servlet-name>
<servlet-class>com.findcn.servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hellServlet</servlet-name>
<url-pattern>/kkk</url-pattern>
</servlet-mapping>
</web-app>
1.设置头部
// 设置响应内容类型
response.setContentType("text/html");
response.setCharacterEncoding("utf-8");
//浏览器刷新 每三秒
response.setHeader("refresh","3");
response.setHeader("Content-Disposition","attachment;filenam="+ URLEncoder.encode(fileName,"UTF-8"));
response.setContentType("image/jpeg");//设置输出为图片
response.setDateHeader("expires",-1);//浏览器不去缓存
response.setHeader("Cache-Control","no-Cache");
response.setStatus(HttpServletResponse.SC_MOVED_TEMPORARILY);//设置请求状态
2.使用 ServletContext
ServletContext context = this.getServletContext();
String uuname = "1223";
// 设置用户名
context.setAttribute("username",uuname);
// 获取设置用户名
String username = (String) context.getAttribute("username");
// 获取配置
String url = context.getInitParameter("url");
3.转发
//请求转发 链接不变
RequestDispatcher requestDispatcher=context.getRequestDispatcher("/pp");
requestDispatcher.forward(request,response);
//重定向链接跳转
response.sendRedirect("/ddd");
4.下载文件
//1.获取下载路径
String realPath = "";
//2.获取文件名
String fileName = realPath.substring(realPath.lastIndexOf("\\")+1);
//3.设置文件下载头部
response.setHeader("Content-Disposition","attachment;filenam="+ URLEncoder.encode(fileName,"UTF-8"));
//4.获取下载文件输入流
FileInputStream in = new FileInputStream(realPath);
//5.创建缓冲区
int len = 0;
byte[] buffer = new byte[1024];
//6.获取OutputStream对象
ServletOutputStream dout = response.getOutputStream();
//7.写入缓冲区
while((len=in.read(buffer))>0){
dout.write(buffer,0,len);
}
in.close();
dout.close();
5.验证码生成
// # 验证码
BufferedImage image = new BufferedImage(80,20,BufferedImage.TYPE_INT_RGB);
Graphics2D g = (Graphics2D) image.getGraphics();
g.setColor(Color.WHITE);//设置背景
g.fillRect(0,0,80,20);
g.setColor(Color.BLUE);//设置文字颜色
g.setFont(new Font(null,Font.BOLD,20));
g.drawString(makeNum(),0,20);//写入随机数
response.setContentType("image/jpeg");//设置输出为图片
response.setDateHeader("expires",-1);//浏览器不去缓存
response.setHeader("Cache-Control","no-Cache");
ImageIO.write(image,"jpg",response.getOutputStream());//浏览器输出
6.生成随机数
private String makeNum(){
Random random = new Random();
String num = random.nextInt(9999999)+"";
StringBuffer sb = new StringBuffer();
for (int i = 0; i < 7-num.length(); i++) {
sb.append("0");
}
num = sb.toString()+num;
return num;
}
7.获取request数据参数
String userName = request.getParameter("username");//获取请求参数
String[] uArr = request.getParameterValues("ids");//获取数组
8.Cookie 操作
//获取cookie
Cookie[] cookies = request.getCookies();
for (int i = 0; i < cookies.length; i++) {
Cookie cookie = cookies[i];
cookie.getName();//获取key
cookie.getValue();//获取value
System.out.println(cookie.getName());
cookie.getName().equals("name");//判断 是否等于
}
//写入cookie
Cookie cookie = new Cookie("cname","到底是啥事");
cookie.setMaxAge(24*60*60);
response.addCookie(cookie);
9.Session
// 时间戳转换
String nowTime = System.currentTimeMillis()+"";//时间戳字符串
Long longTime = Long.getLong(nowTime);//转化为长整型
Date longDate = new Date(longTime);//转化时间日期
SpringBoot
1.简单示例
加载
@Component
// 加载主配置文件
@ConfigurationProperties(prefix = "dog")
// 加载指定配置文件
@PropertySource(value = "classpath:dog.properties")
@Value("阿黄") //赋值变量
// 数据校验
@Validated @Email()//校验数据
// 加载控制器
@RestController
// 路由设置
@RequestMapping("/hello")
测试控制器 Dog
@RestController // 加载控制器
public class HelloController {
@RequestMapping("/hello") //路由设置
public String hello() {
return "hhhha";
}
}
测试用例
@Autowired
private Dog dog; // 自动加载测试类
@Test
void contextLoads() {
System.out.println(dog);
}
2.配置文件
// properties 格式
application.properties
//多环境配置（spring.profiles.active=test）
application-test.properties (server.port=8081)
application-dev.properties (server.port=8082)
//yaml 格式
application.yaml
//多环境配置 --- 分块
spring:
profiles:
active: test
#debug: true
---
server:
port: 8081
spring:
profiles: test
dog:
name: 阿黄
age: 3
---
server:
port: 8082
spring:
profiles: dev
dog:
name: 阿黄
age: 3
3.简单类 示例
package com.lyb.api.pogo;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
// 加载主配置文件
@ConfigurationProperties(prefix = "dog")
public class Dog {
private String name;
private Integer age;
public Dog() {}
public Dog(String name, Integer age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Dog{" + "name='" + name + '\'' + ", age=" + age + '}';
}
}
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