BaseDaoImpl

package com.neusoft.dao.impls;import java.lang.reflect.Field;import java.lang.reflect.ParameterizedType;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.ArrayList;import java.util.List;import org.apache.commons.beanutils.BeanUtils;import com.neusoft.dao.BaseDao;import com.neusoft.exception.IllegalSQLException;import com.neusoft.utils.DBUtils;@SuppressWarnings("unchecked")public class BaseDaoImpl<T> implements BaseDao<T> {protected DBUtils dbUtils;public void setDbUtils(DBUtils dbUtils) {this.dbUtils = dbUtils;}private Class<?> clz; // 对象类型private String table; // 表名 - 从配置文件中读取private String primary; // 主键 - 从配置文件中读取private List<String> fields; // 保存所有字段的 Listpublic BaseDaoImpl() {fields = new ArrayList<String>();clz = (Class<?>) ((ParameterizedType) this.getClass().getGenericSuperclass()).getActualTypeArguments()[0];primary = "user_id";table = "t_user"; // 要改为读取文件for (Field f : clz.getDeclaredFields()) {fields.add(f.getName());}}/** * 保存对象到数据库中 * * @param obj */public void save(T obj) {StringBuffer insert_sql = new StringBuffer("INSERT INTO " + table + "(");StringBuffer value_sql = new StringBuffer(" VALUES('");for (String field : fields) {insert_sql.append(field + ",");try {value_sql.append(BeanUtils.getProperty(obj, field) + "','");} catch (Exception e) {e.printStackTrace();}}insert_sql.setCharAt(insert_sql.length() - 1, ')');value_sql.setCharAt(value_sql.length() - 2, ')');value_sql.setCharAt(value_sql.length() - 1, ' ');String sql = insert_sql.toString() + value_sql.toString();System.out.println(sql);Connection conn = null;Statement stmt = null;try {conn = dbUtils.getConnection();stmt = conn.createStatement();stmt.execute(sql);} catch (SQLException e) {e.printStackTrace();} finally {dbUtils.closeAll(null, stmt, conn);}}/** * 从数据库中删除指定ID的数据 * * @param id */public void deleteById(String id) {String column = primary;deleteByOther(column, id);}/** * 从数据库中删除指定值的数据 * * @param id */public void deleteByOther(String column, String value) {String sql = "DELETE FROM " + table + " WHERE " + column + "='" + value+ "'";System.out.println(sql);Connection conn = null;Statement stmt = null;try {conn = dbUtils.getConnection();stmt = conn.createStatement();stmt.execute(sql);} catch (SQLException e) {e.printStackTrace();} finally {dbUtils.closeAll(null, stmt, conn);}}/** * 从数据库中查找指定ID的数据 * * @param id * @return */public T findById(String id) {List<T> list = findByCondition(primary + "=" + id);if (list.isEmpty()) {return null;} elsereturn list.get(0);}/** * 查找所有的数据 * * @return */public List<T> findAll() {return findByConditions();}/** * 根据多个条件查找 */public List<T> findByConditions(String... conditions) {if (conditions == null) {throw new IllegalSQLException();}StringBuffer sql = new StringBuffer("SELECT * FROM " + table+ " WHERE '1'='1'");for (String c : conditions) {sql.append(" AND " + table + "." + addSingleQuotationMarks(c));}System.err.println(sql);// 连接数据库获取数据Connection conn = null;Statement stmt = null;ResultSet rs = null;List<T> list = null;try {list = new ArrayList<T>();conn = dbUtils.getConnection();stmt = conn.createStatement();rs = stmt.executeQuery(sql.toString());T instance = null;while (rs.next()) {instance = (T) clz.newInstance();for (String cn : fields) {BeanUtils.setProperty(instance, cn, rs.getObject(cn));}list.add(instance);}} catch (SQLException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} finally {dbUtils.closeAll(rs, stmt, conn);}return list;}/** * 按单个条件查找 */public List<T> findByCondition(String condition) {return findByConditions(condition);}/** * 查找某一段的数据 * * @return */public List<T> findSliceByIndex(Integer start, Integer length) {return findByCondition("'1'='1' limit " + start + "," + length);}/** * 获取该表的长度 * * @return */public Integer length() {String sql = "SELECT COUNT(*) from " + table;Connection conn = null;Statement stmt = null;ResultSet rs = null;Integer count = null;try {conn = dbUtils.getConnection();stmt = conn.createStatement();rs = stmt.executeQuery(sql);if (rs.next()) {count = Integer.parseInt(rs.getString(1));}} catch (SQLException e) {e.printStackTrace();} finally {dbUtils.closeAll(rs, stmt, conn);}return count;}public String getNameByID() {// TODO Auto-generated method stubreturn null;}/** * 为字符添加单引号 */private String addSingleQuotationMarks(String temp) {StringBuffer sb = new StringBuffer(temp);return (sb.insert(sb.indexOf("=") + 1, "'")).append("'").toString();}}