如何使用JDBC将列表或集合中的项目插入到SQL表中?
要将数据库的内容插入集合中,
连接到数据库,并使用SELECT查询将表的内容检索到ResultSet对象中。
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
String mysqlUrl = "jdbc:mysql:///mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from MyPlayers");创建一个Java类来保存每条记录的内容,每个列都有一个变量、setter和getter方法(使用合适的datatype)。
例如,如果数据库中的sample表有两个字段,详细信息如下:
- 列名:ID,数据类型:INT(11)
- 列名:Name,数据类型:VARCHAR(255)
那么,类中的变量声明以及setter和getter方法将如下所示:
import java.sql.Date;
public class Sample {
private int ID;
private String Name;
public int getID() {
return ID;
}
public void setID(int id) {
ID = id;
}
public int getName() {
return Name;
}
public void setName(int name) {
Name = name;
}
}对于每条记录,创建一个上述类(Sample)的对象,从ResultSet对象检索每个列的值,并使用其setter方法将其设置为该对象,例如:
Player player = new Player();
player.setID(rs.getInt("ID"));
player.setName(rs.getString("Name"));将对象添加到所需的集合中。
ArrayList<Player> arrayList = new ArrayList<>(); arrayList.add(player);
让我们使用如下所示的CREATE语句在MySQL数据库中创建一个名为**MyPlayers**的表:
CREATE TABLE MyPlayers( ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Date_Of_Birth date, Place_Of_Birth VARCHAR(255), Country VARCHAR(255), PRIMARY KEY (ID) );
现在,我们将使用INSERT语句在**MyPlayers**表中插入7条记录:
insert into MyPlayers values(1, 'Shikhar', 'Dhawan', DATE('1981-12-05'), 'Delhi', 'India');
insert into MyPlayers values(2, 'Jonathan', 'Trott', DATE('1981-04-22'), 'CapeTown', 'SouthAfrica');
insert into MyPlayers values(3, 'Kumara', 'Sangakkara', DATE('1977-10-27'), 'Matale', 'Srilanka');
insert into MyPlayers values(4, 'Virat', 'Kohli', DATE('1988-11-05'), 'Delhi', 'India');
insert into MyPlayers values(5, 'Rohit', 'Sharma', DATE('1987-04-30'), 'Nagpur', 'India');
insert into MyPlayers values(6, 'Ravindra', 'Jadeja', DATE('1988-12-06'), 'Nagpur', 'India');
insert into MyPlayers values(7, 'James', 'Anderson', DATE('1982-06-30'), 'Burnley', 'England');Java类用于保存此表中每个数据:
import java.sql.Date;
public class Player {
private int ID;
private String First_Name;
private String Last_Name;
private Date Date_Of_Birth;
private String Place_Of_Birth;
private String Country;
public int getID() {
return ID;
}
public void setID(int id) {
ID = id;
}
public String getFirst_Name() {
return First_Name;
}
public void setFirst_Name(String first_Name) {
First_Name = first_Name;
}
public String getLast_Name() {
return Last_Name;
}
public void setLast_Name(String last_Name) {
Last_Name = last_Name;
}
public Date getDate_Of_Birth() {
return Date_Of_Birth;
}
public void setDate_Of_Birth(Date date_Of_Birth) {
Date_Of_Birth = date_Of_Birth;
}
public String getPlace_Of_Birth() {
return Place_Of_Birth;
}
public void setPlace_Of_Birth(String place_Of_Birth) {
Place_Of_Birth = place_Of_Birth;
}
public String getCountry() {
return Country;
}
public void setCountry(String country) {
Country = country;
}
}以下JDBC程序检索MyPlayers表的内容,并将它们添加到ArrayList中。
示例
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
public class TableToArrayList {
public static void main(String args[]) throws Exception {
//Registering the Driver
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//Getting the connection
String mysqlUrl = "jdbc:mysql:///mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//Creating a Statement object
Statement stmt = con.createStatement();
//Retrieving the data
ResultSet rs = stmt.executeQuery("select * from MyPlayers");
//Creating an ArrayList object
ArrayList<Player> arrayList = new ArrayList<>();
//Adding the Records of the table to the Array List
while(rs.next()) {
Player player = new Player();
player.setID(rs.getInt("ID"));
player.setFirst_Name(rs.getString("First_Name"));
player.setLast_Name(rs.getString("Last_Name"));
player.setDate_Of_Birth(rs.getDate("Date_Of_Birth"));
player.setPlace_Of_Birth(rs.getString("Place_Of_Birth"));
player.setCountry(rs.getString("Country"));
arrayList.add(player);
}
for (Player obj : arrayList) {
System.out.print("ID: "+obj.getID()+", ");
System.out.print("Name: "+obj.getFirst_Name()+", ");
System.out.print("Age: "+obj.getLast_Name()+", ");
System.out.print("Salary: "+obj.getDate_Of_Birth()+", ");
System.out.print("Country: "+obj.getPlace_Of_Birth()+", ");
System.out.print("Address: "+obj.getCountry());
System.out.println();
}
}
}输出
Connection established...... Records added to the array list..... Contents of the array list: ID: 1, Name: Shikhar, Age: Dhawan, Salary: 1981-12-05, Country: Delhi, Address: India ID: 2, Name: Jonathan, Age: Trott, Salary: 1981-04-22, Country: CapeTown, Address: SouthAfrica ID: 3, Name: Kumara, Age: Sangakkara, Salary: 1977-10-27, Country: Matale, Address: Srilanka ID: 4, Name: Virat, Age: Kohli, Salary: 1988-11-05, Country: Mumbai, Address: India ID: 5, Name: Rohit, Age: Sharma, Salary: 1987-04-30, Country: Nagpur, Address: India ID: 6, Name: Ravindra, Age: Jadeja, Salary: 1988-12-06, Country: Nagpur, Address: India ID: 7, Name: James, Age: Anderson, Salary: 1982-06-30, Country: Burnely, Address: England
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