设置“Dynamic Web Module”为3.0，java版本为1.8（注意：先设置java为1.8，保存后，再设置 Dynamic Web Module”为3.0）
如果项目出现：Cannot change version of project facet Dynamic web module to 3.0的提示信息，则参考下面解决方案，否则跳过此步骤。 原因：该开始选择会报错会提示选择不了这是因为新建项目的时候用了maven-artchetype-webapp由于这个catalog比较老，用的servlet还是2.3的 解决方案： 打开web.xml文件，修改头部为
然后 点击window --> show view --> Navigator 打开org.eclipse.wst.common.project.facet.core.xml文件，或者在项目的工作区间中搜索org.eclipse.wst.common.project.facet.core.xml文件
package com.controller.test.user;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.commons.io.FileUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import com.entity.test.user.User;
import com.service.test.user.UserService;
import com.util.exception.ExceptionUtil;
/**
* 所属类别:控制层方法类（用户）测试
* 用途:用户功能方法
* version:1.0
*/
@Controller
@RequestMapping(value="/user")
public class UserController {
@Autowired
private UserService userService;
public UserController() {
}
//用户登录方法
@RequestMapping(value="/login", method=RequestMethod.POST)
public String login(String username, String password, HttpSession session){
if (null == username || "".equals(username.trim())) {
throw new ExceptionUtil("用户名不能为空");
}
User user = userService.getUserByUsername(username);
if (null == user) {
throw new ExceptionUtil("用户名不存在");
}
if (!user.getPassword().equals(password)) {
throw new ExceptionUtil("密码不正确");
}
session.setAttribute("loginUser", user);
return "redirect:/user/users";
}
//用户列表
@RequestMapping(value="users", method=RequestMethod.GET)
public String list(Model model){
Map users = new HashMap();
for (User user : userService.getAllUsers()) {
users.put(user.getUsername(), user);
}
model.addAttribute("users", users);
return "test/list";
}
//进入添加界面
@RequestMapping(value="add", method=RequestMethod.GET)
public String add(@ModelAttribute("user") User user){
return "test/add";
}
//添加
@RequestMapping(value="add", method=RequestMethod.POST)
public String add(@Validated User user, BindingResult br, @RequestParam(value="attach") MultipartFile[] attachs, HttpServletRequest req) throws IOException{
if (br.hasErrors()) {
return "test/add";
}
String realPath = req.getSession().getServletContext().getRealPath("/resources/upload");
for (int i = 0; i < attachs.length; i++) {
MultipartFile attach = attachs[i];
if (attach.isEmpty()) {
continue;
}
File attachFile = new File(realPath + "/" + attach.getOriginalFilename());
FileUtils.copyInputStreamToFile(attach.getInputStream(), attachFile);
System.out.println(realPath + "/" + attach.getOriginalFilename());
System.out.println(attach.getName());
System.out.println(attach.getOriginalFilename());
System.out.println(attach.getContentType());
}
userService.register(user);
return "redirect:/user/users";
}
//展示用户
@RequestMapping(value="/{username}/show", method=RequestMethod.GET)
public String show(@PathVariable String username, Model model){
model.addAttribute(userService.getUserByUsername(username));
return "test/show";
}
//展示用户
@RequestMapping(value="/{username}/show", method=RequestMethod.GET, params="json")
@ResponseBody
public User show(@PathVariable String username){
return userService.getUserByUsername(username);
}
//进入编辑页面
@RequestMapping(value="/{username}/update", method=RequestMethod.GET)
public String update(@PathVariable String username, Model model){
model.addAttribute(userService.getUserByUsername(username));
return "test/update";
}
//编辑
@RequestMapping(value="/{username}/update", method=RequestMethod.POST)
public String update(@PathVariable String username, @Validated User user, BindingResult br){
if(br.hasErrors()){
return "test/update";
}
userService.update(user);
return "redirect:/user/users";
}
//删除
@RequestMapping(value="/{username}/delete", method=RequestMethod.GET)
public String delete(@PathVariable String username){
userService.removeUser(username);
return "redirect:/user/users";
}
//注销
@RequestMapping(value="/logout", method=RequestMethod.GET)
public String logout(HttpSession session){
session.removeAttribute("loginUser");
return "index";
}
/* //异常处理
@ExceptionHandler(value={ExceptionUtil.class})
public String handleLocalException(ExceptionUtil e, HttpServletRequest req){
req.setAttribute("error", e);
return "test/error";
}
*/
}
web.xml 配置文件
Archetype Created Web Application/WEB-INF/views/index.jsporg.springframework.web.util.IntrospectorCleanupListenerorg.springframework.web.context.ContextLoaderListenercontextConfigLocation
classpath*:spring/applicationContext*.xml
springorg.springframework.web.servlet.DispatcherServletcontextConfigLocationclasspath:springMVC/spring-servlet.xml1spring/setcharacterorg.springframework.web.filter.CharacterEncodingFilterencodingutf-8setcharacter/HiddenHttpMethodFilterorg.springframework.web.filter.HiddenHttpMethodFilterHiddenHttpMethodFilterspringMVC3java.lang.NullPointerException/WEB-INF/views/commons/error/error_web_null.jsp404/WEB-INF/views/commons/error/error_web_404.jsp405/WEB-INF/views/commons/error/error405.jsp500/WEB-INF/views/commons/error/error500.jsp
UserDao.java 用户的Dao层接口
package com.dao.test.user;
import java.util.List;
import com.entity.test.user.User;
public interface UserDao {
//用户注册
public void register(User user);
//根据用户名查找用户
public User findUserByUserName(final String userName);
//查询用户集合
public List findAllUser();
//删除用户（通过用户名)
public boolean deleteByUsername(String username);
//编辑更新用户
public boolean update(User user);
}
UserDaoImpl.java 用户Dao层实现类
package com.dao.test.user;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;
import com.dao.test.user.UserDao;
import com.entity.test.user.User;
@Repository("userDao")
public class UserDaoImpl implements UserDao {
@Autowired
private JdbcTemplate jdbcTemplate;
public UserDaoImpl(){
}
public void register(User user) {
String sqlStr = "insert into user(userName,password) values(?,?)";
Object[] params = new Object[]{user.getUsername(),user.getPassword()};
jdbcTemplate.update(sqlStr, params);
}
public User findUserByUserName(String userName) {
String sqlStr = "select * from user where userName = ?" ;
List users = jdbcTemplate.query(sqlStr,new Object[]{userName} , new UserRowMapper());
if (null != users && !users.isEmpty()) {
return users.get(0);
}
return null;
}
@Override
public boolean deleteByUsername(String username){
int updateNum = jdbcTemplate.update("delete from user where username = '" + username + "'");
if (updateNum != 1) {
return false;
}
return true;
}
@Override
public List findAllUser() {
return jdbcTemplate.query("select * from user", new UserRowMapper());
}
private static class UserRowMapper implements RowMapper {
public User mapRow(ResultSet rs, int rowNum) throws SQLException {
int i = 1;
User user = new User();
user.setId(rs.getInt(i++));
user.setUsername(rs.getString(i++));
user.setPassword(rs.getString(i++));
return user;
}
}
@Override
public boolean update(User user) {
return jdbcTemplate.update("update user set password = " + user.getPassword() + " where username = '" + user.getUsername() + "'") == 1 ? true : false;
}
}
UserService.java 用户service层接口
package com.service.test.user;
import java.util.List;
import com.entity.test.user.User;
public interface UserService {
public boolean register(User user);
public User loginCheck(User user);
public List getAllUsers();
public boolean removeUser(String username);
public User getUserByUsername(String username);
public boolean update(User user);
}
UserServiceImpl.java 用户service层实现类
package com.service.test.user;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.dao.test.user.UserDao;
import com.entity.test.user.User;
@Service("userService")
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;
public UserServiceImpl() {
}
@Override
public List getAllUsers() {
return userDao.findAllUser();
}
@Override
public boolean register(User user) {
User u = userDao.findUserByUserName(user.getUsername());
if (u == null || u.getId() == null || u.getId() == 0) {
userDao.register(user);
return true;
} else {
System.out.println("id=" + u.getId() + ", userName=" + u.getUsername() + ", password=" + u.getPassword());
return false;
}
}
@Override
public User loginCheck(User user) {
User u = userDao.findUserByUserName(user.getUsername());
System.out.println("id=" + u.getId() + ", userName=" + u.getUsername() + ", password=" + u.getPassword());
if (user.getPassword().equals(u.getPassword())) {
return u;
} else {
return null;
}
}
@Override
public boolean removeUser(String username) {
if (userDao.deleteByUsername(username)) {
return true;
}
return false;
}
@Override
public User getUserByUsername(String username) {
return userDao.findUserByUserName(username);
}
@Override
public boolean update(User user) {
return userDao.update(user);
}
}
Context Bound，上下文界定，是Scala为隐式参数引入的一种语法糖，使得隐式转换的编码更加简洁。
隐式参数
首先引入一个泛型函数max，用于取a和b的最大值
def max[T](a: T, b: T) = {
if (a > b) a else b
}
因为T是未知类型，只有运行时才会代入真正的类型，因此调用a >
最近用到企业通讯录，虽然以前也开发过，但是用的是jsf，拼成的树形，及其笨重和难维护。后来就想到直接生成json格式字符串，页面上也好展现。
// 首先取出每个部门的联系人
for (int i = 0; i < depList.size(); i++) {
List<Contacts> list = getContactList(depList.get(i
servlet3.0以后支持异步处理请求，具体是使用AsyncContext ，包装httpservletRequest以及httpservletResponse具有异步的功能，
final AsyncContext ac = request.startAsync(request, response);
ac.s
甲说：
A B两个表总数据量都很大，在百万以上。
idx1 idx2字段表示是索引字段
A B 两表上都有
col1字段表示普通字段
select xxx from A
where A.idx1 between mmm and nnn
and exists (select 1 from B where B.idx2 =
@Repository、@Service、@Controller 和 @Component 将类标识为Bean
Spring 自 2.0 版本开始，陆续引入了一些注解用于简化 Spring 的开发。@Repository注解便属于最先引入的一批，它用于将数据访问层 (DAO 层 ) 的类标识为 Spring Bean。具体只需将该注解标注在 DAO类上即可。同时，为了让 Spring 能够扫描类
先看一下下面的错误代码，对写加了synchronized控制，保证了写的安全，但是问题在哪里呢？
public class testTh7 {
private String data;
public String read(){
System.out.println(Thread.currentThread().getName() + "read data "
网上已经有一大堆的设置步骤的了，根据我遇到的问题，整理一下，如下：
首先先去下载一个mongodb最新版，目前最新版应该是2.6
cd /usr/local/bin
wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-2.6.0.tgz
tar -zxvf mongodb-linux-x86_64-2.6.0.t
1.rust里绑定变量是let，默认绑定了的变量是不可更改的，所以如果想让变量可变就要加上mut。
let x = 1; let mut y = 2;
2.match 相当于erlang中的case，但是case的每一项后都是分号，但是rust的match却是逗号。
3.match 的每一项最后都要加逗号，但是最后一项不加也不会报错，所有结尾加逗号的用法都是类似。
4.每个语句结尾都要加分
