学生宿舍管理系统，JAVA语言，JSP + servlet + javabean

package com.ischoolbar.programmer.dao; import java.lang.reflect.Field; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import org.apache.commons.lang.StringUtils; import com.ischoolbar.programmer.bean.Operator; import com.ischoolbar.programmer.bean.Page; import com.ischoolbar.programmer.bean.SearchProperty; import com.ischoolbar.programmer.util.DbUtil; import com.ischoolbar.programmer.util.StringUtil; /** * 数据库操作基础类 * @author llq *利用泛型和反射机制来抽象数据库基本的增删该查操作 */ public class BaseDao<T> { public final int CURD_ADD = 1; public final int CURD_DELETE = 2; public final int CURD_UPDATE = 3; public final int CURD_SELECT = 4; public final int CURD_COUNT = 5; public Connection con = new DbUtil().getConnection(); private Class<T> t; /** * 构造函数中明确传进来的参数对象 */ @SuppressWarnings("unchecked") public BaseDao(){ Type genericSuperclass = getClass().getGenericSuperclass(); if(genericSuperclass instanceof ParameterizedType){ Type[] actualTypeArguments = ((ParameterizedType)genericSuperclass).getActualTypeArguments(); if(actualTypeArguments.length > 0){ t = (Class<T>) actualTypeArguments[0]; } } } /** * 所有新增插入操作抽象封装 * @param t * @return */ public boolean add(T t){ if(t== null)return false; String buildSql = buildSql(CURD_ADD); try { PreparedStatement prepareStatement = con.prepareStatement(buildSql); Field[] fields = t.getClass().getDeclaredFields(); for(int i=1; i < fields.length; i++){ fields[i].setAccessible(true); prepareStatement.setObject(i, fields[i].get(t)); } return prepareStatement.executeUpdate() > 0; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return false; } /** * 修改实体操作 * @param t * @return */ public boolean update(T t){ String sql = buildSql(CURD_UPDATE); try { PreparedStatement prepareStatement = con.prepareStatement(sql); Field[] declaredFields = this.t.getDeclaredFields(); for(int i = 1; i<declaredFields.length; i++){ declaredFields[i].setAccessible(true); prepareStatement.setObject(i, declaredFields[i].get(t)); } declaredFields[0].setAccessible(true); prepareStatement.setObject(declaredFields.length, declaredFields[0].get(t)); return prepareStatement.executeUpdate() > 0; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return false; } public boolean delete(String[] ids){ String sql = buildSql(CURD_DELETE) + StringUtils.join(ids, ",")+")"; try { PreparedStatement prepareStatement = con.prepareStatement(sql); return prepareStatement.executeUpdate() > 0; } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return false; } /** * 抽象封装所有的分页查询列表操作 * @param page * @return */ public Page<T> findList(Page<T> page){ String sql = buildSql(CURD_SELECT); sql += buidSearchSql(page); sql += " limit " + page.getOffset() + "," + page.getPageSize(); //System.out.println(sql); try { PreparedStatement prepareStatement = con.prepareStatement(sql); prepareStatement = setParams(page, prepareStatement); ResultSet executeQuery = prepareStatement.executeQuery(); List<T> conten = page.getConten(); while(executeQuery.next()){ T entity = t.newInstance(); Field[] declaredFields = t.getDeclaredFields(); for(Field field :declaredFields){ field.setAccessible(true); field.set(entity, executeQuery.getObject(StringUtil.convertToUnderLine(field.getName()))); } conten.add(entity); } page.setConten(conten); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } page.setTotal(getTotal(page)); return page; } /** * 获取符合条件的所有记录数 * @param page * @return */ public int getTotal(Page<T> page){ String sql = buildSql(CURD_COUNT); sql += buidSearchSql(page); try { PreparedStatement prepareStatement = con.prepareStatement(sql); prepareStatement = setParams(page, prepareStatement); ResultSet executeQuery = prepareStatement.executeQuery(); if(executeQuery.next()){ return executeQuery.getInt("total"); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return 0; } /** * 获取所有类型的字段名称 * @param t * @return */ private List<String> getFields(T t){ List<String> fieldsList = new ArrayList<String>(); Field[] declaredFields = t.getClass().getDeclaredFields(); for(Field field : declaredFields){ fieldsList.add(field.getName()); } return fieldsList; } /** * 给构造的查询链接赋值参数 * @param page * @param prepareStatement * @return */ private PreparedStatement setParams(Page<T> page,PreparedStatement prepareStatement){ List<SearchProperty> searchProperties = page.getSearchProperties(); int index = 1; for(SearchProperty searchProperty : searchProperties){ try { if(searchProperty.getOperator() != Operator.IN){ prepareStatement.setObject(index++, searchProperty.getValue()); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return prepareStatement; } /** * 构造查询sql语句 * @param page * @return */ private String buidSearchSql(Page<T> page){ String sql = ""; List<SearchProperty> searchProperties = page.getSearchProperties(); for(SearchProperty searchProperty : searchProperties){ switch(searchProperty.getOperator()){ case GT:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " > ?"; break; } case GTE:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " >= ?"; break; } case EQ:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " = ?"; break; } case LT:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " < ?"; break; } case LTE:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " <= ?"; break; } case LIKE:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " like ?"; break; } case NEQ:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " <> ?"; break; } case IN:{ sql += " and " + StringUtil.convertToUnderLine(searchProperty.getKey()) + " in (" + searchProperty.getValue() + ") "; break; } } } sql = sql.replaceFirst("and", "where"); System.out.println(sql); return sql; } /** * 构造一般查询语句 * @param type * @return */ private String buildSql(int type) { // TODO Auto-generated method stub String sql = ""; switch (type) { case CURD_ADD:{ String sql1 = "insert into " + StringUtil.convertToUnderLine(t.getSimpleName()) + "("; Field[] declaredFields = t.getDeclaredFields(); for(Field field : declaredFields){ sql1 += StringUtil.convertToUnderLine(field.getName()) + ","; } sql1 = sql1.substring(0,sql1.length()-1) + ")"; String sql2 = " values(null,"; String[] params = new String[declaredFields.length-1]; Arrays.fill(params, "?"); sql2 += StringUtils.join(params, ",") + ")"; sql = sql1 + sql2; break; } case CURD_SELECT:{ sql = "select * from " + StringUtil.convertToUnderLine(t.getSimpleName()); break; } case CURD_