标签：java String 跑通 private server 假装 import Java public
Java有点像C++和Python混合品种，方方面面都有点像。本科的时候玩过Java和Android编程，有点基础，现在出来搬砖要捡回去，写一篇博客预习一下。
我一般学代码的步骤都是：定义，变量计算，流程控制，文件操作，数据库，多线程，网络通信。这次把后面三项总结一下。
拿到电脑先配环境，需要装Java的JDK（jdk-8u301-windows-x64.exe），编译器（ideaIU-2021.2.1.exe），mySQL（mysql-installer-community-8.0.26.0.msi），JDBC（mysql-connector-java-8.0.25.tar.gz）
工程路径文件如图：
注意External Libraries中的mysql-conn...，这个是Java连接mySQL的驱动，导入方法是File---Project Structure---Modules---Dependancies---（+）---JARs or Direc...，选择这个文件就行。
工程一共三个文件：
myJDBC.java：使用Java代码操作mySQL数据库进行增删查改
mySocket.java：使用多线程创建socket服务器和客户端
Main.java：如何使用上面文件模块
Main.java
import java.util.Scanner;
import java.util.Vector;
class Java_Demo {
public void SQL_Demo() {
myJDBC mj = new myJDBC("caoyi", "root", "admin123");
if (!mj.connect()) {
System.out.println("connect failure!");
return;
} else {
System.out.println("connect success!");
}
//mj.execute("INSERT INTO info (NAME, SEX, TELE, CODE_TYPE) VALUES ('鬼七', '男', '15600009982', 'excel')");
Vector<Vector<String>> res = mj.query("select * from info", new String[]{"NAME", "SEX", "TELE"}, 3);
if (!mj.disconnect()) {
System.out.println("disconnect failure!");
return;
} else {
System.out.println("disconnect success!");
}
}
public void TCP_Demo() {
Scanner scan = new Scanner(System.in);
mySocket ms = new mySocket();
ms.create_server();
while(true) {
System.out.println("y:run n:exit");
String str = scan.nextLine();
if(str.equals("y")){
ms.create_client();
}else{
System.exit(0);
}
}
}
}
public class Main {
public static void main(String[] args) {
Java_Demo jd = new Java_Demo();
jd.SQL_Demo();
}
}myJDBC.java
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Vector;
class myJDBC {
private String driver;
private String url;
private String user;
private String password;
private Connection conn;
private Statement state;
private ResultSet resultSet;
//构造函数 参数[数据库名, mysql用户名, mysql密码]
protected myJDBC(String db_name, String user, String password) {
this.driver = "com.mysql.jdbc.Driver";
this.url = "jdbc:mysql://localhost:3306/" + db_name; //3306是mysql默认端口
this.user = user;
this.password = password;
}
//连接数据库
public boolean connect() {
try {
Class.forName(driver);
} catch (ClassNotFoundException e) {
//need mysql-connector-java-X.X.XX.jar
return false;
}
try {
conn = DriverManager.getConnection(url, user, password);
if (!conn.isClosed())
{
return true;
}
} catch (SQLException e) {
return false;
}
return true;
}
//断开数据库
public boolean disconnect() {
try{
this.conn.close();
} catch (SQLException e) {
return false;
}
return true;
}
//执行SQL语句
public int execute(String sql) {
//添加条目 "INSERT INTO info (NAME, SEX, TELE, CODE_TYPE) VALUES ('李四', '男', '16759840883', 'python')"
//删除条目 "DELETE FROM info WHERE (ID = '2')"
//修改条目 "UPDATE info SET CODE_TYPE = 'C++' WHERE (ID = '2')"
int stat_id = -1;
try {
state = conn.createStatement();
stat_id = state.executeUpdate(sql);
} catch (SQLException e) {
return 0;
}
return stat_id;
}
//查询内容 以二维容器的形式输出
public Vector<Vector<String>> query(String sql, String[] labels, int label_num) {
Vector query_data = new Vector<Vector<String>>();
try {
state = conn.createStatement();
resultSet = state.executeQuery(sql);
while(resultSet.next()) {
Vector data = new Vector<String>();
for(int i=0;i<label_num;i++)
{
String label = labels[i];
String value = resultSet.getString(label);
data.add(value);
}
query_data.add(data);
}
resultSet.close();
} catch (SQLException e) {
return query_data;
}
return query_data;
}
}mySocket.java
import java.io.*;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;
class server_thread extends Thread {
private ServerSocket server;
private Socket socket;
private int port;
private DataInputStream dis;
private DataOutputStream dos;
public void config(int listen_port) {
this.port = listen_port;
}
public void run() {
try {
server = new ServerSocket(this.port);
System.out.println("waiting connect...");
//服务器循环 一次性连接
while(true) {
socket = server.accept();
System.out.println("connecting!");
dis = new DataInputStream(socket.getInputStream());
String recv = dis.readUTF();
System.out.println(recv);
socket.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
class client_thread extends Thread {
private String server_ip;
private int port;
private Socket socket;
private DataInputStream dis;
private DataOutputStream dos;
public void config(String server_ip, int listen_port) {
this.server_ip = server_ip;
this.port = listen_port;
}
public void run() {
try {
socket = new Socket(server_ip, port);
dos = new DataOutputStream(socket.getOutputStream());
dos.writeUTF("Hello Server, I am Client.");
socket.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public class mySocket {
public void print_info() {
try {
InetAddress ia = InetAddress.getLocalHost();
String local_name = ia.getHostName();
String local_ip = ia.getHostAddress();
System.out.println("HostName: "+local_name);
System.out.println("IPAddr: "+local_ip);
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
void create_server() {
server_thread st = new server_thread();
st.config(8998);
st.start();
}
void create_client() {
client_thread st = new client_thread();
st.config("127.0.0.1", 8998);
st.start();
}
}
标签：java,String,跑通,private,server,假装,import,Java,public 来源： https://blog.csdn.net/XLcaoyi/article/details/120145938
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