SSH做项目时经验总结 （2）

1、
/**
* 用于存放分页数据的类
*/
public class PageBean<T> {

private int pageNum; // 第几页
private int pageSize; // 每页显示的个数
private int totalRecord;// 总记录数

private int startIndex; // 开始索引
private int totalPage; // 总分页数

private List<T> data; // 查询到的分页数据集合

// 动态显示条
private int start;
private int end;

// 生成一个三个参数的构造方法，使对象被创建时，所有参数就都被赋值
public PageBean(int pageNum, int pageSize, int totalRecord) {
super();
this.pageNum = pageNum;
this.pageSize = pageSize;
this.totalRecord = totalRecord;

// 计算开始索引
this.startIndex = (this.pageNum - 1) * this.pageSize;
// 计算总分页数
this.totalPage = (this.totalRecord + this.pageSize - 1) / this.pageSize;

// 动态显示条的初始值
this.start = 1;
this.end = 10;

// 判断总分页数和动态显示的关系，如果总分页数比10小，则动态显示条最大为总分页数
if (this.totalPage <= 10) {
this.end = this.totalPage;
} else {
// 如果总分页数比10大，则动态显示的start值应为当前页减去4页，end值为当前页加上5页
this.start = this.pageNum - 4;
this.end = this.pageNum + 5;
// 当前页为前4页时，如果当start的值为负数时，则start恒定为1，end为10
if (this.start < 1) {
this.start = 1;
this.end = 10;
}
// 当前页为最后5页，则end值肯定比总分页数大，这时需要使end等于总分页数
if (this.end > this.totalPage) {
this.end = this.totalPage;
this.start = this.end - 9;
}
}
}

2、
dao操作
public int getTotalRecord(String condition, Object[] params) {
List<Long> list = this.getHibernateTemplate().find(condition, params);
// 长整形转换成整形intValue()
return list.get(0).intValue();
}

@Override
public List<CrmCourseType> findCourseByCondition(String condition,
Object[] params, int startIndex, int pageSize) {
return this.getHibernateTemplate().execute(
new PageHibernateCallBack<CrmCourseType>().setHql(condition)
.setParams(params).setStartIndex(startIndex)
.setPageSize(pageSize));
}

3、
/**
* 用于分页的回调函数
*
* @author wyj
*
* @param <T>
*/
public class PageHibernateCallBack<T> implements HibernateCallback<List<T>> {
private String hql;  给query对象传入的hql语句
private Object[] params; 传入参数数组
private int startIndex; 传入分页用的开始索引
private int pageSize;   分页用的每页显示个数

// 链式调用
public PageHibernateCallBack<T> setHql(String hql) {
this.hql = hql;
return this;
}
public PageHibernateCallBack<T> setParams(Object[] params) {
this.params = params;
return this;
}
public PageHibernateCallBack<T> setStartIndex(int startIndex) {
this.startIndex = startIndex;
return this;
}
public PageHibernateCallBack<T> setPageSize(int pageSize) {
this.pageSize = pageSize;
return this;
}
@Override
public List<T> doInHibernate(Session session) throws HibernateException,
SQLException {
// 获得query对象
Query query = session.createQuery(hql);
// 遍历多个参数
for (int i = 0; i < params.length; i++) {
// 给query对象设置参数
query.setParameter(i, params[i]);
}
// 设置分页所用到的数据
query.setFirstResult(startIndex);
query.setMaxResults(pageSize);
// 查询所有
return query.list();
}

4、
Service层中添加的操作
//获取总记录数
int totalRecord = this.coursetypeDao.getTotalRecord(condition,params);
//创建pageBean对象
PageBean<CrmCourseType> pageBean = new PageBean<CrmCourseType>(pageNum, pageSize, totalRecord);
//进行分页查询，获得分页数据
List<CrmCourseType> data = this.coursetypeDao.findCourseByCondition(condition, params, pageBean.getStartIndex(), pageBean.getPageSize());
pageBean.setData(data);
return pageBean;

5、
jsp的编写
<span>第<s:property value="pageNum" />/<s:property value="totalPage" />页</span>
<span>
<s:if test="pageNum gt 1">
<a href="javascript:void(0)" onclick="showPage(1)">[首页]</a>  
<a href="javascript:void(0)" onclick="showPage(<s:property value="pageNum - 1" /> )">[上一页]</a>  
</s:if>
<!--动态滚动条 -->
<s:iterator begin="start" end="end" var="num">
<a href="#" onclick="showPage(<s:property value="#num" />)"><s:property value="#num" /></a>
</s:iterator>

<s:if test="pageNum lt totalPage">
<a href="javascript:void(0)" onclick="showPage(<s:property value="pageNum + 1"/> )">[下一页]</a>  
<a href="javascript:void(0)" onclick="showPage(<s:property value="totalPage"/>)">[尾页]</a>
</s:if>
</span>

<script type="text/javascript">
function showPage(num){
//修改隐藏域的值
document.getElementById("pageNum").value = num;
//提交表单
document.forms[0].submit();
}
</script>
form表单
<%-- 添加隐藏域，传入pageNum --%>
<s:hidden id="pageNum" name="pageNum" value="1"/>

6、Iterator标签消失的问题，传入的集合找不到了

7、this关键字，哪个类被new。this就指哪个类

8、BaseDao
public interface BaseDao<T> {
/**
* 添加操作
*
* @param t
*/
public void save(T t);

/**
* 删除操作
*
* @param t
*/
public void delete(T t);

/**
* 修改操作
*
* @param t
*/
public void update(T t);

/**
* 添加或更新操作
*
* @param t
*/
public void saveOrUpdate(T t);

/**
* 通过Id查询
*
* @param id
* @return
*/
public T findById(java.io.Serializable id);

/**
* 查询所有
*
* @return
*/
public List<T> findAll();

/**
* 通过条件查询所有
*
* @param condition
* @param params
* @return
*/
public List<T> findAllByCondition(String condition, Object[] params);

/**
* 条件+分页查询
*
* @param condition
* @param params
* @param startIndex
* @param pageSize
* @return
*/
public List<T> findAllByPage(String condition, Object[] params,
int startIndex, int pageSize);

/**
* 查询总记录数+条件查询
*
* @param condition
* @param params
* @return
*/
public int getTotalRecord(String condition, Object[] params);

/**
* 离线查询
*
* @param criteria
* @return
*/
public List<T> findAllByQBC(DetachedCriteria criteria);

/**
* 使用QBC进行分页查询
*
* @param criteria
* @param condition
* @param params
* @return
*/
public List<T> findAllByPage(DetachedCriteria criteria, int startIndex,
int pageSize);

}

9、
BaseDao的实现类
public class BaseDaoImpl<T> extends HibernateDaoSupport implements BaseDao<T> {

private Class<?> beanClass;
//泛型<T>在编译时是无类型的，只是变量，T只有在运行以后才可以获得具体类型，子类被new时，父类的构造方法会执行
public BaseDaoImpl() {
//ParameterizedType是被参数化了的类型，例如：BaseDaoImpl<CrmClasses>
ParameterizedType parameterizedType = (ParameterizedType) this
.getClass().getGenericSuperclass()获得带泛型参数的class对象;
//getActualTypeArguments()获得所有实际参数值，就是泛型的类型，一般情况下为1个。返回类型为.class的字节码文件
beanClass = (Class<?>) parameterizedType.getActualTypeArguments()[0];
}

public void save(T t) {
this.getHibernateTemplate().save(t);
}

public void delete(T t) {
this.getHibernateTemplate().delete(t);
}

public void update(T t) {
this.getHibernateTemplate().update(t);
}

public T findById(Serializable id) {
return (T) this.getHibernateTemplate().get(beanClass, id);
}

public List<T> findAll() {
// getName()获得全限定名
return this.getHibernateTemplate().find("from " + beanClass.getName());
}

public List<T> findAllByCondition(String condition, Object[] params) {
String hql = "from " + beanClass.getName() + " where 1 = 1 "
+ condition;
return this.getHibernateTemplate().find(hql, params);
}

public List<T> findAllByPage(String condition, Object[] params,
int startIndex, int pageSize) {
String hql = "from " + beanClass.getName() + " where 1 = 1 "
+ condition;
return this.getHibernateTemplate().execute(
new PageHibernateCallBack<T>().setHql(hql).setParams(params)
.setStartIndex(startIndex).setPageSize(pageSize));
}

public int getTotalRecord(String condition, Object[] params) {
String hql = "select count(c) from " + beanClass.getName()
+ " as c where 1 = 1 " + condition;
List<Long> list = this.getHibernateTemplate().find(hql, params);
return list.get(0).intValue();
}

离线查询
public List<T> findAllByQBC(DetachedCriteria criteria) {
return this.getHibernateTemplate().findByCriteria(criteria);
}

public List<T> findAllByPage(DetachedCriteria criteria, int startIndex,
int pageSize) {
return this.getHibernateTemplate().findByCriteria(criteria, startIndex,
pageSize);
}

public void saveOrUpdate(T t) {
this.getHibernateTemplate().saveOrUpdate(t);
}
}

10、
BaseAction
public class BaseAction<T> extends ActionSupport implements ModelDriven<T> {

private T t;

@Override
public T getModel() {
return t;
}

/泛型<T>在编译时是无类型的，只是变量，T只有在运行以后才可以获得具体类型，子类被new时，父类的构造方法会执行
@SuppressWarnings("unchecked")
public BaseAction() {
try {
//ParameterizedType是被参数化了的类型，例如：BaseDaoImpl<CrmClasses>
ParameterizedType parameterizedType = (ParameterizedType) this
.getClass().getGenericSuperclass();
//getActualTypeArguments()获得所有实际参数值，就是泛型的类型，一般情况下为1个。返回类型为.class的字节码文件
Class<T> clazz = (Class<T>) parameterizedType
.getActualTypeArguments()[0];
// 反射创建实例
t = clazz.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
}

// 注入service
private StaffService staffService;
private PostService postService;
private DepartmentService departmentService;
private CoursetypeService coursetypeService;

public StaffService getStaffService() {
return staffService;
}

public void setStaffService(StaffService staffService) {
this.staffService = staffService;
}

b6f5
public PostService getPostService() {
return postService;
}

public void setPostService(PostService postService) {
this.postService = postService;
}

public DepartmentService getDepartmentService() {
return departmentService;
}

public void setDepartmentService(DepartmentService departmentService) {
this.departmentService = departmentService;
}

public CoursetypeService getCoursetypeService() {
return coursetypeService;
}

public void setCoursetypeService(CoursetypeService coursetypeService) {
this.coursetypeService = coursetypeService;
}

//分页数据
private int pageNum = 1;
private int pageSize = 2;

public void setPageNum(int pageNum) {
this.pageNum = pageNum;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public int getPageNum() {
return pageNum;
}
public int getPageSize() {
return pageSize;
}

//简化值栈操作
public void push(Object o){
ActionContext.getContext().getValueStack().push(o);
}
public void put(String key,Object value){
ActionContext.getContext().put(key, value);
}
public void set(String key,Object o){
ActionContext.getContext().getValueStack().set(key, o);
}
public void putSession(String key,Object value){
ActionContext.getContext().getSession().put(key, value);
}
public void putApplication(String key,Object value){
ActionContext.getContext().getApplication().put(key, value);
}
}

11、
文件上传
获取文件上传的三个值
private File schedule; // 上传内容
private String scheduleFileName; // 上传的文件名
private String scheduleContentType; // 上传的类型
上传操作
public String upload() throws IOException {
//获取上传目的地的虚拟路径
String parentDir = ServletActionContext.getServletContext().getRealPath("/WEB-INF/upload");
//给上传文件改名
String fileName = UUID.randomUUID().toString().replace("-", "");
//保存文件
FileUtils.copyFile(schedule, new File(parentDir, fileName));
配置拦截器可通过的扩展名
<interceptor-ref name="defaultStack">
<param name="fileUpload.allowedExtensions">xls,xslx</param>
使用@InputConfig(resultName="uploadInput")修改input视图的name