TCP通信
1.0 客户端的实现
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
public class TCPSocket {
public static void main(String[] args) throws IOException {
Socket socket=new Socket("127.0.0.1",8888);
OutputStream stream = socket.getOutputStream();
stream.write("你好服务器".getBytes());
InputStream inputStream = socket.getInputStream();
byte []bytes=new byte[1024];
int read = inputStream.read(bytes);
System.out.println(new String(bytes,0,read));
socket.close();
}
}
2.0 服务器代码实现
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class TCPServer {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket=new ServerSocket( 8888 );
Socket socket = serverSocket.accept();
InputStream stream = socket.getInputStream();
byte bytes[]=new byte[1024];
int read = stream.read(bytes);
System.out.println(new String(bytes,0,read));
OutputStream outputStream = socket.getOutputStream();
outputStream.write("谢谢收到！".getBytes());
socket.close();
serverSocket.close();
}
}
3.0 TCP通信的综合案例（上传文件从客户端到服务器，并且存储到服务器的硬盘中）
客户端实现
import java.io.*;
import java.net.Socket;
public class TCPSocket {
public static void main(String[] args) throws IOException {
FileInputStream fis=new FileInputStream("D:\\photos\\白雪公主.jpg");
Socket socket=new Socket("127.0.0.1",8888);
OutputStream outputStream = socket.getOutputStream();
byte []bytes=new byte[1024];
int len=0;
while((len=fis.read(bytes))!=-1)
{
outputStream.write(bytes,0,len);
}
socket.shutdownOutput();
/*
*上传完文件，给服务器写一个结束标记
* 禁用此套接字的输出流
* 对于TCP套接字，任何之前的写入的数据都将被发送，
* 并且后跟TCP的正常连接终止序列
* */
InputStream inputStream = socket.getInputStream();
byte []bytes1=new byte[1024];
int len1=inputStream.read(bytes1);
System.out.println(new String(bytes1,0,len1));
socket.close();
fis.close();
}
}
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class TCPServer{
public static void main(String[] args) throws IOException {
ServerSocket serverSocket=new ServerSocket(8888);
Socket socket = serverSocket.accept();
InputStream inputStream = socket.getInputStream();
File file=new File("D:\\upload");
if(!file.exists())
{
file.mkdirs();
}
FileOutputStream fos=new FileOutputStream(file+"\\白雪公主.jpg") ;
byte[] bytes=new byte[1024];
int len=0;
while((len=inputStream.read(bytes))!=-1)
{
fos.write(bytes,0,len);
}
socket.getOutputStream().write("上传成功！".getBytes());
serverSocket.close();
fos.close();
socket.close();
}
}
函数式接口
1.0 概念
2.0利用Lambda表达式的执行延迟（接口作为方法的参数传递）
优化日志的案例（输入编号，输出字符串拼接后的字符串 先字符串拼接后执行 所以可能会浪费资源）
public interface MessageBuilder {
public abstract String bulidMessage();
}
public class Main{
public static void main(String[] args) {
String msg1="Hello";
String msg2="World";
String msg3="Java";
showlog(1,()->msg1+msg2+msg3
);
}
private static void showlog(int grade,MessageBuilder ms) {
if(grade==1)
{
System.out.println(ms.bulidMessage());
}
}
}
3.0 接口作为方法的返回值传递
数组排序案例
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Comparator;
public class Main{
public static Comparator getCompare()
{
return new Comparator() {
@Override
public int compare(String o1, String o2) {
return o2.length()-o1.length();//长度降序
}
};
}
public static void main(String[] args) {
String arr[]={"jin,27","jimin,25","v,25"};
Arrays.sort(arr,(o1,o2)->o2.length()-o1.length());
System.out.println(Arrays.toString(arr));
}
}
打印结果：
[jimin,25, jin,27, v,25]
常用的函数式接口
1.0 Supplier接口
练习 找出数组中的最大值 并打印
import java.util.function.Supplier;
public class Main{
public static int getMax(Supplier sup)
{
Integer integer = sup.get();
return integer;
}
public static void main(String[] args) {
int Max = getMax(() -> {
int arr[] = {34, 234, 52, 5, 65};
int max = arr[0];
for (int i : arr) {
if (i > max) max = i;
}
return max;
});
System.out.println(Max);//234
}
}
2.0 Consumer接口
import java.util.function.Consumer;
public class Main {
public static void conSume(String name, Consumer con)
{
con.accept(name);
}
public static void main(String[] args) {
conSume("金泰亨",(name)->{
System.out.println(name);
});
}
}
默认方法 andThen
练习 格式化打印信息 格式 姓名：XX，年龄：XX
import java.util.function.Consumer;
public class Main {
public static void conSume(String []arr, Consumer con1,Consumer con2)
{
for (String s : arr) {
con1.andThen(con2).accept(s);
}
}
public static void main(String[] args) {
String arr[]={"Suga,26","Jimin,25","JK,23"};
conSume(arr,(s)->{
String s1 = s.split(",")[0];
System.out.print("姓名："+s1+",");
},(s)->{
String s2 = s.split(",")[1];
System.out.println("年龄："+s2);
});
}
}
打印结果：
姓名：Suga,年龄：26
姓名：Jimin,年龄：25
姓名：JK,年龄：23
3.0 predicate接口
基本使用
import java.util.function.Predicate;
public class Main{
public static void CheckString(String s, Predicate pre)
{
System.out.println(pre.test(s));//false
}
public static void main(String[] args) {
String s="abcde";
CheckString(s,(str)->{
return s.length()>5;
});
}
}
默认方法 and
import java.util.function.Predicate;
public class Main{
public static void checkString(String s, Predicate pre1,Predicate pre2)
{
boolean test = pre1.and(pre2).test(s);
System.out.println(test);
}
public static void main(String[] args) {
String s="abcdef";
checkString(s,(str)->
str.length()>5
,(str)->str.contains("a")
);
}
}
默认方法 or
默认方法 negate
4.0 Function接口
练习将String->Integer+10 Integer->String
import java.util.function.Function;
public class Main{
public static void Method(String s, Function fun1,Function fun2)
{
String apply = fun1.andThen(fun2).apply(s);
System.out.println(apply);
}
public static void main(String[] args) {
String s="23";
Method(s,(str)->{
int i = Integer.parseInt(s);
return i+10;
},(i)->{
return i+"";
});
}
}