第一次在android上使用jdbc连接数据库,记录下。最开始写的demo连接的本地电脑的mysql数据库,只能模拟器访问,有大神知道怎么设置请回复赐教,后来改成外网地址又出现查询不到的情况,后来才发现是字符编码不统一的问题。
jar包:可搜索mysql-connector-java下载最新的,也可从我项目里copy
权限:
<uses-permission android:name="android.permission.INTERNET"/>
注意:查询操作要在子线程中
runnable = new Runnable() {
private Connection con = null;
@Override
public void run() {
try {
Class.forName("com.mysql.jdbc.Driver");
//122.112.226.122为ip地址
//3306为端口号,sun_graduation为数据库名称,第二个test为数据库登录账户,密码test1234
con = DriverManager.getConnection("jdbc:mysql://122.112.226.122:3306/sun_graduation?useUnicode=true&characterEncoding=gbk", "test", "test1234");
} catch (SQLException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
//搜索
startSearch(con);
} catch (final SQLException e) {
e.printStackTrace();
}
}
public void startSearch(Connection con) throws SQLException {
try {
//查询表名为“xhzd_surnfu”的列zi值为mResult的列为pinyin的值
String sql = "select * from xhzd_surnfu where zi = '" + edtKey.getText().toString() + "'";
// String sql = "select pinyin from xhzd_surnfu where id = 1";
Statement stmt = con.createStatement();//创建Statement
ResultSet rs = stmt.executeQuery(sql);//ResultSet类似Cursor
StringBuilder sbResult = new StringBuilder();
//ResultSet最初指向第一行
while (rs.next()) {
//rs.getString("列名")=对应列名的字段值
if (!TextUtils.isEmpty(rs.getString("pinyin"))) {
sbResult.append("拼音:").append(rs.getString("pinyin")).append("\n");
}
if (!TextUtils.isEmpty(rs.getString("bushou"))) {
sbResult.append("部首:").append(rs.getString("bushou")).append("\n");
}
if (!TextUtils.isEmpty(rs.getString("bihua"))) {
sbResult.append("笔画:").append(rs.getString("bihua")).append("\n");
}
if (!TextUtils.isEmpty(rs.getString("xiangjie"))) {
sbResult.append("详解:").append(rs.getString("xiangjie")).append("\n");
}
}
if (sbResult.length() == 0) {
sbResult.append("搜索结果为空");
}
Bundle bundle = new Bundle();
bundle.putString("result", sbResult.toString());
Message msg = new Message();
msg.setData(bundle);
myHandler.sendMessage(msg);
rs.close();
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (con != null)
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
};
获取数据库连接时遇到查询中文字符就查不到的情况,后来发现是字符编码不统一引起的。ide的默认字符编码时utl-8而数据库的是gbk,就一直搜索不到结果。加上useUnicode=true&characterEncoding=gbk 即可
关于useUnicode=true&characterEncoding=gbk
https://blog.youkuaiyun.com/afgasdg/article/details/6941712
注意:查询完之后关闭资源
if (con != null)
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}