jsp+servlet+jdbc简单的登陆操作，却没有报错也没有登录成功

Question

部分代码：

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

// 1.字符处理

request.setCharacterEncoding("utf8");

response.setCharacterEncoding("utf8");

response.setHeader("content-type", "text/html;charset=utf8");

// 3. 获得保存在session的验证码

HttpSession session = request.getSession();

// 4.获取打印类

PrintWriter out = response.getWriter();

// 5.获取验证码，判断验证码是否正确

String randCode = request.getParameter("code");

String rand = session.getAttribute("IdentifyCode").toString();

if (randCode != null && !randCode.trim().equals("")) {

if (!randCode.trim().equals(rand)) {// 验证码不通过

out.write("CodeFalse");

return;

}

// 接收前端传进来的账号和密码

// 接收数据

// 1.得到请求参数

String username = request.getParameter("username");

String password = request.getParameter("password");

System.out.println(username+password);

// 2.登录

UserService service = new UserService();

try {

User user = service.login(username, password);

if (user != null) {// 登陆成功

out.write("LoginSuc");

return;

} else {

System.out.println("LoginServlet登陆失败");

out.write("LoginFail");

return;

}

} catch (Exception e) {

e.printStackTrace();

System.out.println("LoginServlet登陆失败");

out.write("LoginFail");

}

}

}

UserDao的代码

public User login(String username, String password) throws SQLException {

String sql = "select * from user where username=? and password=?";

QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());

return runner.query(sql, new BeanHandler<User>(User.class),username,password);

}

控制台输出结果

111111111111

十二月 31, 2017 2:00:59 上午 com.mchange.v2.log.MLog <clinit>

信息: MLog clients using java 1.4+ standard logging.

十二月 31, 2017 2:01:00 上午 com.mchange.v2.c3p0.C3P0Registry banner

信息: Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug? true; trace: 10]

十二月 31, 2017 2:01:01 上午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager

信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 1bqzwb29s1arxty7eq2dop|40634bec, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1bqzwb29s1arxty7eq2dop|40634bec, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql:///chatroom, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]

LoginServlet登陆失败

 

Answer 1

查看了一下user 返回的是null值，这是为什么？排除密码或用户名查询的时候匹配不上这个可能