jdbc工具类封装

Posted 2020-08-03

封装

package util;

import java.sql.Connection;  
import java.sql.DriverManager;  
import java.sql.PreparedStatement;  
import java.sql.ResultSet;  
import java.sql.SQLException;  
  
/** 
 * @author sawyer 2014下午1:20:16 
 *  
 */  
  
public class JdbcUtil {  
    private Connection conn = null;  
    private PreparedStatement stmt = null;  
    private ResultSet rs = null;  
    private static String driver = "com.mysql.jdbc.Driver";  
    private String url = "jdbc:mysql://localhost:3306/Student";  
    private String user = "root";  
    private String password = "root";  
  
    /** 
     * Get the driver 
     */  
    static {  
  
    }  
    /** 
     * Connect the database 
     */  
    public Connection getCon() {  
        try {  
            Class.forName(driver);  
        } catch (ClassNotFoundException e) {  
            e.printStackTrace();  
        }  
        try {  
            conn = (Connection) DriverManager  
                    .getConnection(url, user, password);  
        } catch (SQLException e) {  
            e.printStackTrace();  
        }  
        return conn;  
    }  
  
    /** 
     * @param sql 
     * @param obj 
     *Update 
     */
    public int update(String sql, Object... obj) { 
        int count = 0; 
        conn = getCon(); 
        try { 
            stmt = conn.prepareStatement(sql); 
            if (obj != null) { 
                for (int i = 0; i < obj.length; i++) { 
                    stmt.setObject(i + 1, obj[i]); 
                } 
            } 
            count = stmt.executeUpdate(); 
        } catch (SQLException e) { 
            e.printStackTrace(); 
        } finally { 
            close(); 
        } 
        return count; 
    } 
 
    /** 
     * @param sql 
     * @param obj 
     * Query 
     */ 
    public ResultSet Query(String sql, Object... obj) { 
        conn = getCon(); 
        try { 
            stmt = conn.prepareStatement(sql); 
            while (obj != null) { 
                for (int i = 0; i < obj.length; i++) { 
                    stmt.setObject(i + 1, obj[i]); 
                } 
            } 
            rs = stmt.executeQuery(); 
        } catch (SQLException e) { 
            e.printStackTrace(); 
        } finally { 
            close(); 
        } 
        return rs; 
    } 
  
    /** 
     * CLose the resource 
     */  
    public void close() {  
        try {  
            if (rs != null) {  
                rs.close();  
            }  
        } catch (SQLException e) {  
            e.printStackTrace();  
        } finally {  
            try {  
                if (stmt != null) {  
                    stmt.close();  
                }  
            } catch (SQLException e) {  
                e.printStackTrace();  
            } finally {  
                if (conn != null) {  
                    try {  
                        conn.close();  
                    } catch (SQLException e) {  
                        e.printStackTrace();  
                    }  
                }  
            }  
        }  
    }  
}  

model

package model;

import java.io.Serializable;

public class Student implements Serializable{
	private int id;
	private int age;
	private String name;
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}

　　

测试

package model;

import java.sql.ResultSet;
import java.sql.SQLException;

import util.JdbcUtil;

public class Test {
	public static void main(String[] args) {
		testInsert();
		testQuery();
	}
	public static void testInsert(){
		Student s=new Student();
		s.setId(12);
		s.setAge(23);
		s.setName("xxt");
		JdbcUtil u=new JdbcUtil();
		String sql="insert into T_Student(id,age,name) values( ?,?,?)";
		int result=u.update(sql, s.getId(),s.getAge(),s.getName());
		System.out.println(result);
	}
	public static void testQuery(){
		String sql="select * from T_Student where age=?";
		Student s=new Student();
		s.setAge(23);
		JdbcUtil u=new JdbcUtil();
		ResultSet rs=u.Query(sql, s.getAge());
		try {
			if(rs.next()){
				//s.setName(rs.getString("name"));
				System.out.println(rs.getString("name"));//s.getName(rs.getString("name"))
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}