java JDBC (四)

package cn.sasa.demo4;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

public class TestJDBCUtil {
    public static void main(String[] args) throws SQLException {
        Connection conn = JDBCUtil.getConn();

        String sql = "SELECT * FROM product;";
        PreparedStatement pstate = conn.prepareStatement(sql);
        ResultSet rs = pstate.executeQuery();

        ArrayList<Product> plist = new ArrayList<Product>();
        while(rs.next()) {
            Product p = new Product(rs.getInt("pid"),
                    rs.getString("pname"),
                    rs.getDouble("price"),
                    rs.getString("ptype"),
                    rs.getString("create_tm")
                    );
            plist.add(p);
        }

        JDBCUtil.close(conn, pstate, rs);

        for(var p : plist) {
            System.out.println(p.getPname() +"\t"+ p.getPrice());
        }
    }
}

package cn.sasa.demo4;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/***
 * JDBC 工具类
 * @author THTF
 *
 */
public class JDBCUtil {

    private JDBCUtil() {}

    private static Connection conn;

    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://192.168.0.207:3306/mydb";
            String user = "root";
            String pwd = "XXXXXXXXXXXXXX1";
            conn = DriverManager.getConnection(url, user, pwd);
        }catch(Exception ex){
            throw new RuntimeException(ex + "数据库连接失败");
        }
    }

    /**
     * 获得连接
     */
    public static Connection getConn() {
        return conn;
    }

    /**
     * 关闭资源
     */
    public static void close(Connection con, Statement state, ResultSet rs) {
        if(con != null) {
            try {
                con.close();
            }catch(SQLException ex){

            }
        }
        if(state != null) {
            try {
                state.close();
            }catch(SQLException ex){

            }
        }
        if(rs != null) {
            try {
                rs.close();
            }catch(SQLException ex){

            }
        }
    }

    public static void close(Connection con, Statement state) {
        if(con != null) {
            try {
                con.close();
            }catch(SQLException ex){

            }
        }
        if(state != null) {
            try {
                state.close();
            }catch(SQLException ex){

            }
        }
    }
}

package cn.sasa.demo4;

public class Product {
    private int pid;
    private String pname;
    private double price;
    private String ptype;
    private String create_tm;

    public Product() {}
    public Product(int pid, String pname,double price,
            String ptype, String create_tm) {
        this.pid = pid;
        this.pname = pname;
        this.price = price;
        this.ptype = ptype;
        this.create_tm = create_tm;
    }
    public int getPid() {
        return pid;
    }
    public void setPid(int pid) {
        this.pid = pid;
    }
    public String getPname() {
        return pname;
    }
    public void setPname(String pname) {
        this.pname = pname;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    public String getPtype() {
        return ptype;
    }
    public void setPtype(String ptype) {
        this.ptype = ptype;
    }
    public String getCreate_tm() {
        return create_tm;
    }
    public void setCreate_tm(String create_tm) {
        this.create_tm = create_tm;
    }
}