public class TransactionFilter implements Filter {
// 声明集合保存静态资源扩展名
private static Set<String> staticResourceExtNameSet;
static {
staticResourceExtNameSet = new HashSet<>();
staticResourceExtNameSet.add(".png");
staticResourceExtNameSet.add(".jpg");
staticResourceExtNameSet.add(".css");
staticResourceExtNameSet.add(".js");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
// 前置操作:排除静态资源
HttpServletRequest request = (HttpServletRequest) servletRequest;
String servletPath = request.getServletPath();
if (servletPath.contains(".")) {
String extName = servletPath.substring(servletPath.lastIndexOf("."));
if (staticResourceExtNameSet.contains(extName)) {
// 如果检测到当前请求确实是静态资源,则直接放行,不做事务操作
filterChain.doFilter(servletRequest, servletResponse);
// 当前方法立即返回
return ;
}
}
Connection connection = null;
try{
// 1、获取数据库连接
connection = JDBCUtils.getConnection();
// 重要操作:关闭自动提交功能
connection.setAutoCommit(false);
// 2、核心操作
filterChain.doFilter(servletRequest, servletResponse);
// 3、提交事务
connection.commit();
}catch (Exception e) {
try {
// 4、回滚事务
connection.rollback();
} catch (SQLException ex) {
ex.printStackTrace();
}
// 页面显示:将这里捕获到的异常发送到指定页面显示
// 获取异常信息
String message = e.getMessage();
// 将异常信息存入请求域
request.setAttribute("systemMessage", message);
// 将请求转发到指定页面
request.getRequestDispatcher("/").forward(request, servletResponse);
}finally {
// 5、释放数据库连接
JDBCUtils.releaseConnection(connection);
}
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {}
@Override
public void destroy() {}
}
<filter>
<filter-name>txFilterfilter-name>
<filter-class>com.alex.imperial.court.filter.TransactionFilterfilter-class>
filter>
<filter-mapping>
<filter-name>txFilterfilter-name>
<url-pattern>/*url-pattern>
filter-mapping>
确保异常回滚
谨防数据库连接提前释放
假设有下列页面地址:
/WEB-INF/pages/apple.html
/WEB-INF/pages/banana.html
/WEB-INF/pages/orange.html
/WEB-INF/pages/grape.html
/WEB-INF/pages/egg.html
public class ViewBaseServlet extends HttpServlet {
private TemplateEngine templateEngine;
@Override
public void init() throws ServletException {
// 1.获取ServletContext对象
ServletContext servletContext = this.getServletContext();
// 2.创建Thymeleaf解析器对象
ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(servletContext);
// 3.给解析器对象设置参数
// ①HTML是默认模式,明确设置是为了代码更容易理解
templateResolver.setTemplateMode(TemplateMode.HTML);
// ②设置前缀
String viewPrefix = servletContext.getInitParameter("view-prefix");
templateResolver.setPrefix(viewPrefix);
// ③设置后缀
String viewSuffix = servletContext.getInitParameter("view-suffix");
templateResolver.setSuffix(viewSuffix);
// ④设置缓存过期时间(毫秒)
templateResolver.setCacheTTLMs(60000L);
// ⑤设置是否缓存
templateResolver.setCacheable(true);
// ⑥设置服务器端编码方式
templateResolver.setCharacterEncoding("utf-8");
// 4.创建模板引擎对象
templateEngine = new TemplateEngine();
// 5.给模板引擎对象设置模板解析器
templateEngine.setTemplateResolver(templateResolver);
}
protected void processTemplate(String templateName, HttpServletRequest req, HttpServletResponse resp) throws IOException {
// 1.设置响应体内容类型和字符集
resp.setContentType("text/html;charset=UTF-8");
// 2.创建WebContext对象
WebContext webContext = new WebContext(req, resp, getServletContext());
// 3.处理模板数据
templateEngine.process(templateName, webContext, resp.getWriter());
}
}
<context-param>
<param-name>view-prefixparam-name>
<param-value>/WEB-INF/pages/param-value>
context-param>
<context-param>
<param-name>view-suffixparam-name>
<param-value>.htmlparam-value>
context-param>
public class ModelBaseServlet extends ViewBaseServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 在doGet()方法中调用doPost()方法,这样就可以在doPost()方法中集中处理所有请求
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 1.在所有request.getParameter()前面设置解析请求体的字符集
request.setCharacterEncoding("UTF-8");
// 2.从请求参数中获取method对应的数据
String method = request.getParameter("method");
// 3.通过反射调用method对应的方法
// ①获取Class对象
Class<? extends ModelBaseServlet> clazz = this.getClass();
try {
// ②获取method对应的Method对象
Method methodObject = clazz.getDeclaredMethod(method, HttpServletRequest.class, HttpServletResponse.class);
// ③打开访问权限
methodObject.setAccessible(true);
// ④通过Method对象调用目标方法
methodObject.invoke(this, request, response);
} catch (Exception e) {
e.printStackTrace();
// 重要提醒:为了配合 TransactionFilter 实现事务控制,捕获的异常必须抛出。
throw new RuntimeException(e);
}
}
}
public class ImperialCourtConst {
public static final String LOGIN_FAILED_MESSAGE = "账号、密码错误,不可进宫!";
public static final String ACCESS_DENIED_MESSAGE = "宫闱禁地,不得擅入!";
}
public class MD5Util {
/**
* 针对明文字符串执行MD5加密
* @param source
* @return
*/
public static String encode(String source) {
// 1.判断明文字符串是否有效
if (source == null || "".equals(source)) {
throw new RuntimeException("用于加密的明文不可为空");
}
// 2.声明算法名称
String algorithm = "md5";
// 3.获取MessageDigest对象
MessageDigest messageDigest = null;
try {
messageDigest = MessageDigest.getInstance(algorithm);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
// 4.获取明文字符串对应的字节数组
byte[] input = source.getBytes();
// 5.执行加密
byte[] output = messageDigest.digest(input);
// 6.创建BigInteger对象
int signum = 1;
BigInteger bigInteger = new BigInteger(signum, output);
// 7.按照16进制将bigInteger的值转换为字符串
int radix = 16;
String encoded = bigInteger.toString(radix).toUpperCase();
return encoded;
}
}
<configuration debug="true">
<appender name="STDOUT"
class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>[%d{HH:mm:ss.SSS}] [%-5level] [%thread] [%logger] [%msg]%npattern>
<charset>UTF-8charset>
encoder>
appender>
<root level="INFO">
<appender-ref ref="STDOUT" />
root>
<logger name="com.atguigu" level="DEBUG" additivity="false">
<appender-ref ref="STDOUT" />
logger>
configuration>