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字符字节流，前升后降

浏览器下载需要设置两个头 responese .setHeader() 一个设置返回的文件类型

		FileInputStream fis = new FileInputStream(path);//创建字节输出流ServletOutputStream sos = response.getOutputStream();//执行输出操作int len = 1;byte[] b = new byte[1024];while((len = fis.read(b)) != -1) {sos.write(b, 0, len);}/*方法内可以不关流*/sos.close();//告知客户端要下载的文件response.setHeader("content-disposition", "attachment;filename=" + filename);response.setHeader("content-type", "application/octet-stream");  

text/plain 表示文本文件的默认值。
application/octet-stream 表示所有其他情况的默认值

https://blog.csdn.net/qq_39007603/article/details/128566928

https://blog.csdn.net/woacptp/article/details/80199713

一、pandas是什么？

package Sort;import com.sun.deploy.util.StringUtils;
import org.omg.IOP.Encoding;import java.io.*;
import java.lang.reflect.Field;
import java.util.*;
import java.util.function.Consumer;public class Sort {public static void main(String[] args) throws IOException {//test01();//test02();//test03();// test04();test06();}public static void test01(){Integer[] ints = new Integer[]{2,3,45,20,12321,1};
//        Arrays.sort(ints,Collections.reverseOrder());
//        Collections.sort(Arrays.asList(ints), new Comparator<int[]>() {
//            @Override
//            public int compare(int[] o1, int[] o2) {
//                return 0;
//            }
//        });//lambda
//        Arrays.stream(ints).forEach(value -> System.out.println(value));//o1-o2 是升序//o2-o1 是降序//lambdaArrays.stream(ints).sorted(new Comparator<Integer>() {@Overridepublic int compare(Integer o1, Integer o2) {return o2-o1;   //是什么排序？？？？？？}}).forEach(new Consumer<Integer>() {@Overridepublic void accept(Integer integer) {System.out.println(integer);}});}public static void test02(){List<Student> list = new ArrayList<>();list.add(new Student(1, "A", 20, 180));list.add(new Student(2, "B", 23, 175));list.add(new Student(3, "C", 22, 190));list.add(new Student(4, "D", 21, 175));list.add(new Student(5, "E", 20, 185));list.stream().sorted(new Comparator<Student>() {@Overridepublic int compare(Student o1, Student o2) {//前升后降//身高升序，年龄升序if(o1.getHeight() == o2.getHeight()){return o1.getAge()-o2.getAge();}else{return o1.getHeight() - o2.getHeight();}}}).forEach(new Consumer<Student>() {@Overridepublic void accept(Student student) {System.out.println(student);}});}public static void test03(){System.out.println("_wrhwiefwi".matches("^([A-Za-z0-9_]{1,})$"));}public static void test04() throws IOException {//降sql读取到该本地中去String sql = "select * from user limit 10";ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(sql.getBytes());int length = 0 ;byte[] arr = new byte[1024];String fileName = "./"+ UUID.randomUUID()+".sql";FileOutputStream fileOutputStream = new FileOutputStream(fileName);while ( (length = byteArrayInputStream.read(arr)) != -1 ){fileOutputStream.write(arr,0,length);}//关闭流byteArrayInputStream.close();fileOutputStream.close();}public static void test05() throws IOException {//降sql读取到该本地中去String sql = "select * from user limit 10";StringReader stringReader = new StringReader(sql);FileWriter fileWriter = new FileWriter("./test05.sql");int length = 0;char[] chars = new char[1024];while( (length = stringReader.read(chars)) != -1 ){fileWriter.write(chars,0,length);}stringReader.close();fileWriter.close();}public static void test06() throws IOException {FileReader reader = new FileReader("./test05.sql");BufferedReader bufferedReader = new BufferedReader(reader);FileWriter writer = new FileWriter("./test06.sql",true);BufferedWriter bufferedWriter = new BufferedWriter(writer);String name = "";while ( (name = bufferedReader.readLine()) != null ){bufferedWriter.write(name);bufferedWriter.newLine();  //添加System.out.println(name);}bufferedWriter.flush();bufferedReader.close();bufferedWriter.close();}}