190218

在HTML中显示图片
1.一般将图片放在static/img文件夹中
2.格式<img src="img/1.png">
3.若将图片放在其他没有权限直接访问的地方,则需要自定义目录映射.

//WebConfigurer
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class WebAppConfigurer extends WebMvcConfigurerAdapter {
	@Override
	public void addResourceHandlers(ResourceHandlerRegistry registry) {
	registry.addResourceHandler("/img2/**").addResourceLocations("file:C:/Users/");
	super.addResourceHandlers(registry);
	}
}

//htmldemo
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<img src="img/1.png">
<img src="img2/3.png">
</body>
</html>

访问地址http://localhost:8080/img2/3.png

IO操作

package com.zz.io;

import java.io.File;

public class Demo1 {
		
		public static void main(String[] args) {
			File f=new File("D://1111/hhh.txt");
			
			System.out.println(f.exists());
			System.out.println(f.isDirectory());//判断路径是不是文件夹,如果是文件夹就返回true
			System.out.println(f.list());//返回,路径下,所有的文件数组
	//		System.out.println(f.delete());//删除文件
		}

}

package com.zz.io;

import java.io.File;
import java.io.IOException;

public class Demo2 {

		public static void main(String[] args) {
			
			//createNewFile("D:/1111/hanhanniu.txt");
			//createNewFolder("D:/1111/2019");
			//createNewFolder2("D:/1111/2019/java/spring");
			checkFiles2("D:/1111");
		}
		/**
		 * 创建一个文件
		 * @param filePath
		 */
		public static void createNewFile(String filePath) {
			File f=new File(filePath);
			try {
				f.createNewFile();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
		/**
		 * 创建一个文件夹
		 * @param filePath
		 */
		public static void createNewFolder(String filePath) {
			File f=new File(filePath);
			f.mkdir();
		}
		/**
		 * 创建夹中夹
		 * @param filePath
		 */
		public static void createNewFolder2(String filePath) {
			File f=new File(filePath);
			f.mkdirs();
		}
		/**
		 * 查看文件
		 * @param filePath
		 */
		public static void checkFiles(String filePath) {
			File f=new File(filePath);
			File[] fs=f.listFiles();
			for(File temp:fs) {
				System.out.println(temp.getName());
			}
		}
		
		public static void checkFiles2(String filePath) {
			File f=new File(filePath);
			File[] fs=f.listFiles();
			for(File temp:fs) {
				if(temp.isDirectory()) {//如果当前文件是文件夹
					System.out.println(temp.getName());
					checkFiles2(temp.getPath());
					//递归的方式:自己调用自己
				}else {
					System.out.println(temp.getName());
				}
				
			}
		}
}

package com.zz.io;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class Demo3 {
	
		public static void main(String[] args) {
			
			File f=new File("D://1111/hhh.txt");
			try {
				//输入流
				FileInputStream fileinput=new FileInputStream(f);
				byte[] b=new byte[(int)f.length()];
				fileinput.read(b);
				fileinput.close();
				String c=new String(b);
				System.out.println(c);
			} catch ( IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
}

package com.zz.io;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class Demo4 {
	
	public static void main(String[] args) {
		
		File f=new File("D://1111/hhh.txt");
		
		try {
			//输出流
			FileOutputStream out=new FileOutputStream(f);
			String str="你好美";
			//String 转byte数组
			byte[] b=str.getBytes();
			out.write(b);
			out.close();
		} catch ( IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

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