Android连接MySQL数据库实现方法详解

//必须加
<uses-permission android:name="android.permission.INTERNET"/>
//可不加
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

//主线程  以监听为例
Thread thread=null;
public void onClick(View view){
      if(thread==null){
          //连接数据库不能在主线程，单开一个线程
          thread=new Thread(new Runnable(){
              User user=UserDao.findUser(1);
          });
      }
}

//连接工具类
public class ConnectionUtils {
    public static Connection getConn(){
        String url="jdbc:mysql://255.255.255.1:3306/databaseName"+"?useUnicode=true&characterEncoding=utf-8&useSSL=false";
        String username="firstUser";
        String password="123456";
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
        Connection connection_jdbc = null;
        try {
            DriverManager.setLoginTimer(2000);
            connection_jdbc= DriverManager.getConnection(url,username,password);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        return connection_jdbc;
    }
    public static boolean close(Connection connection){
        if(connection!=null){
            try {
                connection.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
}

//存储内容类
public class User {
    private int id;
    private String username;
    private String password;
    private int storyid;
    public int getId() {
        return id;
    }
    public String getUsername() {
        return username;
    }
    public String getPassword() {
        return password;
    }
    public int getStoryid() {
        return storyid;
    }
    public User(int id,String username,String password,int storyid){
        this.id=id;
        this.username=username;
        this.password=password;
        this.storyid=storyid;
    }
    public String toString(){
        String str="id:"+id+" username:"+username+" password:"+password+" storyid:"+storyid;
        return str;
    }
}

//数据访问对象类
public class Dao {
    private Connection conn;
    public static User findUser(int id){
        //尽量复用通道，避免反复连接造成延迟
        if(conn==null){
            conn=ConnectionUtils.getConn();
        }
        try {
            Statement statement=conn.createStatement();
            String sql="select * from mysql where id ='"+id+"'";
            ResultSet resultSet=statement.executeQuery(sql);
            Boolean bool = resultSet.next();//先移动指针再获取值
            //如果ResultSet无结果，next()返回false
            if(bool){
               int resultSetId=resultSet.getInt("id");
               String resultSetSex=resultSet.getString("sex");
               String resultSetName=resultSet.getString("name");
               User user=new User(resultSetId,resultSetSex,resultSetName);
               return user;
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        //确定不使用再关闭通道
        //ConnectionUtils.close(conn);
    }
}