Android通过JDBC连接MySql数据库
android中联网访问权限的添加
- AndroidManifest文件中要添加权限
...
</application>
<uses-permission android:name="android.permission.INTERNET" />
</manifest>关闭Windows防火墙
- （点击控制面板, 进入之后在控制面板中找到Windows防火墙, 点进去之后全部选择关闭就行了）
找到自己的Ip地址
之所以要找到自己的Ip地址是因为App实在虚拟机中运行的，所以localhost指虚拟机，并不是当前电脑，所以需要当前电脑的ip地址链接MYSQL数据库。
* 右击网络 -> 属性, 进入之后看到这个画面
点击红线那里进入到下图
之后点击详细信息就可以看到IP地址了
数据库增删改查
数据库的增删改查我给放到了一个.class文件中，用来方便以后其他的程序调用
//链接数据库的函数
public static Connection openConnection(String url, String user,
String password) {
Connection conn = null;
try {
final String DRIVER_NAME = "com.mysql.jdbc.Driver";
//动态加载MySQL驱动
Class.forName(DRIVER_NAME);
//获取MySql数据库的连接对象
conn = DriverManager.getConnection(url, user, password);
} catch (ClassNotFoundException e) {
conn = null;
} catch (SQLException e) {
conn = null;
}
return conn;
}
//执行查询，插入，更新动作的函数，此处返回了一个ArrayList类型的引用对象，方便app调用数据
public static ArrayList<Detail> query(Connection conn, String sql) {
ArrayList<Detail> detailArray = new ArrayList<Detail>();
if (conn == null) {
return null;
}
Statement statement = null;
ResultSet result = null;
try {
//从数据库连接对象中获取一个用来传递SQL语句的对象
statement = conn.createStatement();
result = statement.executeQuery(sql);
if (result != null && result.first()) {
while (!result.isAfterLast()) {
//getXXX("columnIndex")方法用来获取数据表中该列的数据并返回
int idColumnIndex = result.getInt("id");
String titleColumnIndex = result.getString("title");
String contentColumnIndex = result.getString("Content");
//此处用来检测数据是否被读出，可以删除掉
System.out.println(titleColumnIndex+"\n");
detailArray.add(new Detail(titleColumnIndex, contentColumnIndex, idColumnIndex));
result.next();
}
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (result != null) {
result.close();
result = null;
}
if (statement != null) {
statement.close();
statement = null;
}
} catch (SQLException sqle) {
}
}
return detailArray;
}
//数据库查询是否存在目标数据的操作函数
public static boolean execSQL(Connection conn, String sql) {
boolean execResult = false;
if (conn == null) {
return execResult;
}
Statement statement = null;
try {
statement = conn.createStatement();
if (statement != null) {
execResult = statement.execute(sql);
}
} catch (SQLException e) {
execResult = false;
}
return execResult;
}开发环境：eclipse + MySQL
开发语言：java
用了一小的阅读app来解释如何连接MySql数据库
1. 首先创建一个Android Application Project
- android_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<ListView
android:id="@+id/list_items"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:divider="#ffffff"
android:dividerHeight="1dip"
></ListView>
</RelativeLayout>我为ListView自动一个Item的格式
- Item.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/RelativeLayout"
android:paddingBottom="4dip"
android:paddingLeft="12dip"
android:paddingRight="12dip"
>
<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:paddingLeft="6dip"
android:paddingTop="6dip"/>
<TextView
android:id="@+id/username"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingTop="6dip"
android:textColor="#000"
android:textSize="18sp"
/>
<TextView
android:id="@+id/birthday"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/username"
android:maxLines="2"
android:paddingRight="20dip"
android:textColor="#000"
/>
</RelativeLayout>
之后自定义一个设配器，用来为android_main.xml中的Listview设配Item.xml中的样式
- MyAdapter.class
public class MyAdapater extends ArrayAdapter<Detail>{
private int reasourceID;
Context context;
public MyAdapater(Context context, int textViewReasourceId, Detail[] objects) {
super(context, textViewReasourceId, objects);
reasourceID = textViewReasourceId;
this.context = context;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Detail user = (Detail)getItem(position);
View view;
view = LayoutInflater.from(this.getContext()).inflate(reasourceID, null);
//获取Item.xml页面中的控件
TextView userName = (TextView)view.findViewById(R.id.username);
TextView userBirthdy = (TextView)view.findViewById(R.id.birthday);
ImageView userImageView = (ImageView)view.findViewById(R.id.image);
//为控件赋值
userName.setText(user.getTitle());
userBirthdy.setText(user.getContent().length()>15?user.getContent().substring(0, 15)+"...":user.getContent());
userImageView.setImageResource(R.drawable.ic_launcher);
return view;
}
}
之后为listview设置item样式 ( MainActivity.class )
ListView listView = (ListView)this.findViewById(R.id.list_items);
MyAdapater adapter = new MyAdapater(this, R.layout.item, array);
listView.setAdapter(adapter);为listview设置点击跳转事件 ( MainActivity.class )
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int position, long id) {
// View就是条目视图
// position就是ListView的条目，即第几条
// id 就是Adapter返回的ID
Intent intent = new Intent();
//利用Intent在两个页面之间传值
String str = id+"";
intent.putExtra("str", str);
intent.setClass(MainActivity.this, SecondActivity.class);
MainActivity.this.startActivity(intent);
}
});从MySql数据库中获取标题
在Android中连接数据库不能在主线程中使用，所以我新建了一个线程从中获取数据
static class MyThread extends Thread{
@Override
public void run() {
conn = Util.openConnection(serverDB, serverUser, serverPw);
String sqlStr = "select * from cp";
temp = Util.query(conn, sqlStr);
array = new Detail[temp.size()];
temp.toArray(array);
Flag = 1;
}
}- MainActivity.class
package com.example.listviewdemo1;
import android.os.Bundle;
import java.sql.Connection;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;
public class MainActivity extends Activity {
private static final String serverDB = "jdbc:mysql://117.87.93.205:3306/programming_c";
private static final String serverUser = "zetile";
private static final String serverPw = "123456";
private static Connection conn;
private static int Flag = 0;
public static Detail[] array;
private static ArrayList<Detail> temp;
static class MyThread extends Thread{
@Override
public void run() {
conn = Util.openConnection(serverDB, serverUser, serverPw);
String sqlStr = "select * from cp";
temp = Util.query(conn, sqlStr);
array = new Detail[temp.size()];
temp.toArray(array);
Flag = 1;
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MyThread myThread = new MyThread();
myThread.start();
//设置标志位让主线程在新建的线程运行之后在运行
while(Flag != 1){
}
Flag = 0;
ListView listView = (ListView)this.findViewById(R.id.list_items);
MyAdapater adapter = new MyAdapater(this, R.layout.item, array);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int position, long id) {
// View就是条目视图
// position就是ListView的条目，即第几条
// id 就是Adapter返回的ID
Intent intent = new Intent();
//利用Intent在两个页面之间传值
String str = id+"";
intent.putExtra("str", str);
intent.setClass(MainActivity.this, SecondActivity.class);
MainActivity.this.startActivity(intent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
运行截图
