• SQL练习


    记得导包

    /class TestUser

    package com.JDBCsql;
    
    import lombok.Data;
    
    @Data
    public class TestUser {
        private Integer id;
        private String name;
        private Integer pasword;
        private String mail;
        private String root;
    }
    

      /class TestMysql

    package com.JDBCsql;
    
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.Properties;
    
    public class TestMysql {
           private static String DRIVER=null;
           private static String URL=null;
           private static  String USERNAME = null;   	
       	   private static  String PASSWORD = null;
       	static{
    		try {
    			FileInputStream fis 
    			= new FileInputStream("src/db.properties");
    			Properties pt = new Properties();
    			pt.load(fis);
    			DRIVER = pt.getProperty("DRIVER");
    			URL = pt.getProperty("URL");
    			USERNAME = pt.getProperty("USERNAME");
    			PASSWORD = pt.getProperty("PASSWORD");
    		} catch (FileNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
       	public static Connection getConn(){
    		Connection conn=null;
    		try {
    			/*加载驱动*/
    //			System.out.println(DRIVER);
    			Class.forName(DRIVER);
    			/*连接数据库*/
    			conn= DriverManager.getConnection(URL, USERNAME, PASSWORD);
    			
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return conn;
    	}
    	//关闭连接
    	public static void close(Connection conn){
    		try {
    			conn.close();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    	}
    	//关闭连接
    	public static void close(PreparedStatement ps){
    		try {
    			ps.close();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    	}
    	//关闭连接
    	public static void close(ResultSet rs){
    		try {
    			rs.close();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		
    	}
    	
    	
    	public static int executeUpdate(String sql,Object... papram) {
    		// TODO Auto-generated method stub
    		Connection conn =getConn();
    		int result=0;
    		try {
    			PreparedStatement pst = conn.prepareStatement(sql);
    			if (papram!=null) {
    				for (int i = 0; i < papram.length; i++) {
    					pst.setObject(i+1, papram[i]);
    				}
    			}
    			result =pst.executeUpdate();
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally {
    			close(conn);
    		}
    		return result;
    
    	}
    	
    }
    

      /class TestMenu

    package com.JDBCsql;
    
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Scanner;
    
    public class TestMenu {
    
         public static int show(Scanner scanner,TestUser testUser1,String a4) {
        	System.out.println("查询全部用户-----------------1");
     		System.out.println("根据ID查询用户………………………………………2");
     		System.out.println("根据姓名查询用户--------------3");
     		System.out.println("请输入要做的操作:");
     		int d=scanner.nextInt();
     		switch (d) {
    		case 1:
    			getUser1(testUser1);
    			
    			RootUser.show(a4, scanner, testUser1);
    			break;
            case 2:
            	
            	getUser2(testUser1, scanner);
            	System.out.println(testUser1.toString());
            	System.out.println("=========================================");
    			RootUser.show(a4, scanner, testUser1);
    			break;
            case 3:
            	getUser3(testUser1, scanner);
            	System.out.println(testUser1.toString());
    			System.out.println("=========================================");
    			RootUser.show(a4, scanner, testUser1);
    			break;
    		default:
    			break;
    		}
    		return d;
    	}
         public static int getUser1(TestUser testUser1){
     		Connection conn = 	TestMysql.getConn();
     		List<TestUser>list=new ArrayList<TestUser>();
     		ResultSet index ;//记录行数
     		PreparedStatement pst = null;
     		String sql =  "select * from user ";		
     		try {
     			pst = conn.prepareStatement(sql);
     			
     			index = pst.executeQuery();
     			while (index.next()) {
     				TestUser testUser=new TestUser();
     				testUser.setId(index.getInt("id"));
     				testUser.setName(index.getString("name"));
     				testUser.setPasword(index.getInt("pasword"));
     				testUser.setMail(index.getString("mail"));
     				testUser.setRoot(index.getString("root"));
     				list.add(testUser);
     			}	
     			
     			for (TestUser testUser2 : list) {
    				System.out.println(testUser2.getId()+" "+testUser2.getName()+" "+testUser2.getPasword()+" "+testUser2.getMail()+" "+testUser2.getRoot());
    				System.out.println("=========================================");
    			}
     		} catch (SQLException e) {
     			// TODO Auto-generated catch block
     			e.printStackTrace();
     		}finally {
     			try {
     				pst.close();
     				conn.close();
     			} catch (SQLException e) {
     				// TODO Auto-generated catch block
     				e.printStackTrace();
     			}
     			
     		}
    		return 0;
     		
     	}
         public static int getUser2(TestUser testUser1,Scanner scanner){
     		Connection conn = 	TestMysql.getConn();		
     		ResultSet index ;//记录行数
     		PreparedStatement pst = null;
     		System.out.println("请输入要查询的ID:");
        	String s=scanner.next();
        	testUser1.setId(Integer.valueOf(s));
     		String sql =  "select * from user where id='"+testUser1.getId()+"'";		
     		try {
     			pst = conn.prepareStatement(sql);
     			
     			index = pst.executeQuery();
     			while (index.next()) {
     				testUser1.setId(index.getInt("id"));
     				testUser1.setName(index.getString("name"));
     				testUser1.setPasword(index.getInt("pasword"));
     				testUser1.setMail(index.getString("mail"));
     				testUser1.setRoot(index.getString("root"));
     			}
     		} catch (SQLException e) {
     			// TODO Auto-generated catch block
     			e.printStackTrace();
     		}finally {
     			try {
     				pst.close();
     				conn.close();
     			} catch (SQLException e) {
     				// TODO Auto-generated catch block
     				e.printStackTrace();
     			}
     			
     		}
    		return 0;
     		
     	}
         public static int getUser3(TestUser testUser1,Scanner scanner){
     		Connection conn = 	TestMysql.getConn();		
     		ResultSet index ;//记录行数
     		System.out.println("请输入要查询的用户名:");
     		String s=scanner.next();
     		testUser1.setName(s);
     		PreparedStatement pst = null;
     		String sql =  "select * from user where name='"+testUser1.getName()+"'";		
     		try {
     			pst = conn.prepareStatement(sql);
     			
     			index = pst.executeQuery();
     			while (index.next()) {
     				testUser1.setId(index.getInt("id"));
     				testUser1.setName(index.getString("name"));
     				testUser1.setPasword(index.getInt("pasword"));
     				testUser1.setMail(index.getString("mail"));
     				testUser1.setRoot(index.getString("root"));
     			}	
     		} catch (SQLException e) {
     			// TODO Auto-generated catch block
     			e.printStackTrace();
     		}finally {
     			try {
     				pst.close();
     				conn.close();
     			} catch (SQLException e) {
     				// TODO Auto-generated catch block
     				e.printStackTrace();
     			}
     			
     		}
     		return 0;	
     	}
    }
    

      /class PublicUser

    package com.JDBCsql;
    
    import java.util.Scanner;
    import com.JDBCsql.TestUser;
    public class PublicUser {
    
    	public static int show(String a4,Scanner scanner,TestUser testUser1){
        	System.out.println("登录成功。。。。");
    		System.out.println("======================");
    		System.out.println("欢迎登录主窗体");
    		System.out.println(a4+"您好"+"    "+"您的权限是"+testUser1.getRoot());
    		System.out.println("======================");
    		System.out.println("修改自己的信息---------------1");
    		System.out.println("查询自己的信息………………………………………2");
    		System.out.println("退出主程序------------------3");
    		int d=scanner.nextInt();
    		switch (d) {
    		case 1:
    			System.out.println("请输入您的新用户名:");
    			String q=scanner.next();
    			
    			testUser1.setName(q);
    			System.out.println("请输入您的新密码:");
    			String q1=scanner.next();
    			testUser1.setPasword(Integer.valueOf(q1));
    			System.out.println("请输入您的新邮箱:");
    			String q3=scanner.next();
    			testUser1.setMail(q3);
    		    testUser1.getId();
    			update1(testUser1);
    			System.out.println("信息修改成功!");
    			PublicUser.show(a4, scanner, testUser1);
    			break;
    			
    		case 2:
    			System.out.println("您的用户名为:"+testUser1.getName()+"您的用户密码是:"+testUser1.getPasword()+"您的邮箱是:"+testUser1.getMail()+"您的权限是:"+testUser1.getRoot());
    			PublicUser.show(a4, scanner, testUser1);
    			break;
            
    		default:
    			break;
    		}
    		return d;     	
        }
    
    	private static int update1(TestUser testUser1) {
    		// TODO Auto-generated method stub
    		return TestMysql.executeUpdate("update user set name=?,pasword=?,mail=?where id=?",testUser1.getName(),testUser1.getPasword(),testUser1.getMail(),testUser1.getId());
    	}
    }
    

      /class RootUser

    package com.JDBCsql;
    
    import java.util.Scanner;
    
    public class RootUser {
    	public static int show(String a4,Scanner scanner,TestUser testUser1){
        	System.out.println("登录成功。。。。");
    		System.out.println("======================");
    		System.out.println("欢迎登录主窗体");
    		System.out.println(a4+"您好"+"    "+"您的权限是"+"管理员");
    		System.out.println("======================");
    		System.out.println("添加用户---------------1");
    		System.out.println("删除用户………………………………………2");
    		System.out.println("修改用户---------------3");
    		System.out.println("查询用户………………………………………4");
    		System.out.println("退出程序---------------5");
    		int d=scanner.nextInt();
    		switch (d) {
    		case 1:
    			System.out.println("请输入您想要创建的用户名:");
    			String q=scanner.next();
    			testUser1.setName(q);
    			System.out.println("请输入您想要创建的用户密码:");
    			String q1=scanner.next();
    			testUser1.setPasword(Integer.valueOf(q1));
    			System.out.println("请输入新用户的邮箱:");
    			String q3=scanner.next();
    			testUser1.setMail(q3);
    			String q4="管理员";
    			testUser1.setRoot(q4);
    			add(testUser1);
    			System.out.println("新用户创建成功!");
    			RootUser.show(a4, scanner, testUser1);
    			break;
    			
    		case 4:
    			TestMenu.show(scanner, testUser1, a4);
    //			RootUser.show(a4, scanner, testUser1);
    			break;
            case 2:
            	System.out.println("请输入您想要删除用户的ID:");
    			String q5=scanner.next();
    			testUser1.setId(Integer.valueOf(q5));
    			delete(Integer.valueOf(q5));
    			System.out.println("用户删除成功!");
    			RootUser.show(a4, scanner, testUser1);
            	break;
            case 3:
            	System.out.println("请输入您想要修改的用户ID:");
    			String v=scanner.next();
    			testUser1.setId(Integer.valueOf(v));
            	System.out.println("请输入您想要修改的用户名:");
    			String v1=scanner.next();
    			testUser1.setName(v1);
    			System.out.println("请输入您想要修改的用户密码:");
    			String v2=scanner.next();
    			testUser1.setPasword(Integer.valueOf(v2));
    			System.out.println("请输入您想要修改的用户的邮箱:");
    			String v3=scanner.next();
    			testUser1.setMail(v3);
    			System.out.println("请输入您想要修改的用户的权限(管理员/普通用户):");
    			String v4=scanner.next();
    			testUser1.setRoot(v4);
    			update(testUser1);
    			System.out.println("新用户创建成功!");
    			RootUser.show(a4, scanner, testUser1);
            	break;
    		default:
    			break;
    		}
    		return d;     	
        }
    
    	private static int update(TestUser testUser1) {
    		// TODO Auto-generated method stub
    		return TestMysql.executeUpdate("update user set name=?,pasword=?,mail=?,root=? where id=?",testUser1.getName(),testUser1.getPasword(),testUser1.getMail(),testUser1.getRoot(),testUser1.getId());
    	}
    
    	private static int delete(Integer q5) {
    		// TODO Auto-generated method stub
    		return TestMysql.executeUpdate("delete from user where id=?",q5);
    	}
    
    	private static int add(TestUser testUser1) {
    		// TODO Auto-generated method stub
    		return TestMysql.executeUpdate("insert into user (name,pasword,mail,root) values (?,?,?,?)",testUser1.getName(),testUser1.getPasword(),testUser1.getMail(),testUser1.getRoot());
    	}
    
    	
    }
    

      /class TestView

    package com.JDBCsql;
    
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.Scanner;
    
    public class TestView {
    	public static int delete(int id){
    		return TestMysql.executeUpdate("delete from user where id=?",id);
    		
    	}
    	public static int update(TestUser testUser){
    		return TestMysql.executeUpdate("update user set name=?,pasword=?,mail=?,root=? where id=?",testUser.getName(),testUser.getPasword(),testUser.getMail(),testUser.getRoot(),testUser.getId());
    	}
    	public static int update1(TestUser testUser){
    		return TestMysql.executeUpdate("update user set name=?,pasword=?,mail=?where id=?",testUser.getName(),testUser.getPasword(),testUser.getMail(),testUser.getId());
    	}
    	public static int add(TestUser testUser){
    		return TestMysql.executeUpdate("insert into user (name,pasword,mail,root) values (?,?,?,?)",testUser.getName(),testUser.getPasword(),testUser.getMail(),testUser.getRoot());
    	}
    	public static TestUser getUser(TestUser testUser){
    		Connection conn = 	TestMysql.getConn();		
    		TestUser testUser4 =new TestUser();
    		ResultSet index ;//
    		PreparedStatement pst = null;
    		String sql =  "select * from user where name='"+testUser.getName()+"' and pasword='"+testUser.getPasword()+"'";		
    		try {
    			pst = conn.prepareStatement(sql);
    			
    			index = pst.executeQuery();
    			if (index.next()==false) {
    				return new TestUser();
    			}
    			else {
    				testUser4.setId(index.getInt("id"));
    				testUser4.setName(index.getString("name"));
    				testUser4.setPasword(index.getInt("pasword"));
    				testUser4.setMail(index.getString("mail"));
    				testUser4.setRoot(index.getString("root"));
    			}	
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally {
    			try {
    				pst.close();
    				conn.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    			
    		}
    		return testUser4;	
    	}
    	public static void main(String[] args) {
    		System.out.println("欢迎使用neusoft用户管理系统");
    		System.out.println("======================");
    		System.out.println("用户注册----------------1");
    		System.out.println("用户登录----------------2");
    		System.out.println("退出系统----------------3");
    		Scanner scanner=new Scanner(System.in);
    		int key = scanner.nextInt();
    		switch (key) {
    		case 2:
    			System.out.println("欢迎");
    			System.out.println("======================");
    			System.out.println("");
    			String a1=scanner.next();
    			TestUser testUser =new TestUser();
    			testUser.setName(a1);
    			System.out.println("输入用户名");
    			String a2=scanner.next();
    			testUser.setPasword(Integer.valueOf(a2));
    			System.out.println("输入邮箱");
    			String a3=scanner.next();
    			testUser.setMail(a3);
    			System.out.println("输入权限");
    			String a7=scanner.next();
    			testUser.setRoot(a7);
    			add(testUser);
    			System.out.println("");
    			TestView.main(args);
    			break;
    		case 1:
    			System.out.println("");
    			System.out.println("======================");
    			System.out.println("");
    			String a4=scanner.next();
    			TestUser testUser1 =new TestUser();
    			testUser1.setName(a4);
    			System.out.println("룺");
    			int a5=scanner.nextInt();
    			testUser1.setPasword(a5);
    			testUser1=TestView.getUser(testUser1);
    			if (testUser1==null) {
    				System.out.println("");
    			} else if (testUser1.getRoot().equals("")==true) {
    				PublicUser.show(a4, scanner, testUser1);
    			}else  {
    				RootUser.show(a4, scanner, testUser1);
    			}
    
    			break;
    
    		default:
    			scanner.close();
    			break;
    		}
    	}
    }
    

      

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  • 原文地址:https://www.cnblogs.com/lc-java/p/7397882.html
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