jdbc工具类封装

Posted 2020-09-18

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();
        }
    }
}