JDBC使用sql语句

1. JDBC---连接数据库
   
   

java与数据库连接需要驱动，这个驱动则是JDBC，连接的时候需要ip+端口号+dbname 还要用户名和密码

1. 改java文件的编码方式--在项目名点右键属性----把编码方式改成UTF-8
   
   改变页面jsp的编码方式--在MyEclipse点右键--preferences中改
   
   点项目名右键属性：

建立4个包

必须要写这个方法：、

声明 执行

1. 当增、改、删的时候跟上面的程序差不多
   
   可是当查的时候只能
   
   

package com.softteem.dbweb.db;

import java.sql.DriverManager;

import java.sql.Connection;

import java.sql.ResultSet;

public class ConnDB {

public static void getConn(){

		try {
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			String url="jdbc:sqlserver://128.0.38.13:1433;databaseName=three";
			String user="sa";
			String password="sasa";
			Connection conn=DriverManager.getConnection(url, user, password);
			String sql="insert into teacher values('李老师',35,1)";
			conn.createStatement().execute(sql);
			conn.close();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public static void findAll(){
		try {
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			String url="jdbc:sqlserver://128.0.38.13:1433;databaseName=three";
			String user="sa";
			String password="sasa";
			Connection conn=DriverManager.getConnection(url, user, password);
			String sql="select * from teacher";
			ResultSet rs=conn.createStatement().executeQuery(sql);
			while(rs.next()){
				int tno=rs.getInt("tno");
				String tname=rs.getString("tname");
				int sex=rs.getInt("sex");
				int age=rs.getInt("age");
				System.out.println("tno="+tno+",tname="+tname+",sex="+sex+",age="+age);
			}
			conn.close();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	public static void main(String[] args) {
		findAll();
	}

}

1. 把相同代码合在一起
   
   
   
   
   
   
   
   

更简便的方法：

1. 作业
   
   

package com.softteem.dbweb.bean;

public class Teacher {

private int tno;

private String tname;

private int sex;

private int age;

public int getTno() {
	return tno;
}
public void setTno(int tno) {
	this.tno = tno;
}
public String getTname() {
	return tname;
}
public void setTname(String tname) {
	this.tname = tname;
}
public int getSex() {
	return sex;
}
public void setSex(int sex) {
	this.sex = sex;
}
public int getAge() {
	return age;
}
public void setAge(int age) {
	this.age = age;
}

}

package com.softteem.dbweb.dao;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import com.softteem.dbweb.bean.Teacher;

import com.softteem.dbweb.db.ConnDB;

public class TeacherDao {

public static void insertOrUpdate(String sql){

	try {
		Connection conn=ConnDB.getConn();
		conn.createStatement().execute(sql);
		ConnDB.closeConn(conn);
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}

}
public static List<Teacher> findAll(String sql){
	List<Teacher> list=new ArrayList<Teacher>();

	try {
		Connection conn=ConnDB.getConn();
		ResultSet rs=conn.createStatement().executeQuery(sql);
		while(rs.next()){
			int tno=rs.getInt("tno");
			String tname=rs.getString("tname");
			int sex=rs.getInt("sex");
			int age=rs.getInt("age");

			Teacher bean=new Teacher();
			bean.setTno(tno);
			bean.setTname(tname);
			bean.setSex(sex);
			bean.setAge(age);
			list.add(bean);
		}
		ConnDB.closeConn(conn);
	} catch (Exception e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	return list;
}
public static void main(String[] args) {
	List<Teacher> list=findAll("select * from teacher");
	for (Teacher t : list) {
		System.out.println("编号："+t.getTno()+"姓名："+t.getTname()+"年龄："+t.getAge()+"性别："+t.getSex());
	}
}

}

package com.softteem.dbweb.db;

import java.sql.DriverManager;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.List;

public class ConnDB {

public static Connection getConn(){

Connection conn=null;

try {

Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

String url="jdbc:sqlserver://128.0.38.13:1433;databaseName=three";

String user="sa";

String password="sasa";

conn=DriverManager.getConnection(url, user, password);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return conn;

}

public static void closeConn(Connection conn){

if(conn!=null){

try {

conn.close();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}