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import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/**
* test 数据库连接操作
* @author Administrator
*
/
public class DataAccess {
private static final String driver="com.mysql.jdbc.Driver";
private static final String url="jdbc:mysql://localhost:3306/test
?useUnicode=true&characterEncoding=UTF-8&useSSL=true";
private static final String username="root";
private static final String passwork="2315806986";
private static Connection conn=null;
static{
try{
//加载驱动
Class.forName(driver);
}catch(Exception ex){
ex.printStackTrace();
}
}
public static Connection getConnection() throws Exception{
if(conn==null){
//连接数据库
conn=DriverManager.getConnection(url, username, passwork);
return conn;
}
//判断数据库连接是否成功
if(conn!=null){
System.out.println("连接正常");
}else{
System.out.println("连接异常");
}
return conn;
}
public static Boolean closeConnection(){
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return true;
}
}
public class User {
private int id;
private String name;
private int age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
public class UserDAO {
/**
* 查询数据库里面所有的数据
* @return
*/
public static ArrayList<User> quaryAll(){
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
ArrayList<User> list = new ArrayList<User>();
try {
conn = DataAccess.getConnection();
String sql = "select * from test;";
stmt = conn.prepareStatement(sql);
rs = stmt.executeQuery();
while (rs.next()) {
User item = new User();
item.setAge(rs.getInt("age"));
item.setName(rs.getString("name"));
item.setId(rs.getInt("id"));
list.add(item);
}
return list;
} catch (Exception ex) {
ex.printStackTrace();
return null;
} finally {
if (rs != null) {
try {
rs.close();
rs = null;
} catch (Exception e) {
e.printStackTrace();
}
}
if (stmt != null) {
try {
stmt.close();
stmt = null;
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
import java.util.ArrayList;
public class Test {
public static void main(String[] args) {
ArrayList<User> userList = UserDAO.quaryAll();
for(User user : userList){
System.out.println("查询出来的id是:"+user.getId());
System.out.println("查询出来的名字是:"+user.getName());
System.out.println("查询出来的年龄是:"+user.getAge());
}
}
}
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