285 lines
7.1 KiB
Java
285 lines
7.1 KiB
Java
package com.utils;
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import java.lang.reflect.Field;
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import java.sql.Connection;
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import java.sql.DriverManager;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.sql.ResultSetMetaData;
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import java.sql.SQLException;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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public class DBUtil {
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// 四大金刚
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String dname = Utils.getPeoperties("dbname");
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String driver = "com.mysql.jdbc.Driver";// 驱动名称
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String url = "jdbc:mysql://"+Utils.getPeoperties("dburl")+":"+Utils.getPeoperties("dbport")+"/"+dname+"?useUnicode=false&characterEncoding=UTF-8&useOldAliasMetadataBehavior=true&autoReconnect=true&useSSL=false";// 连接
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String username = Utils.getPeoperties("dbusername");// 用户名
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String password = Utils.getPeoperties("dbpassword");// 密码
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// 三剑客
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Connection con = null;// 连接对象
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PreparedStatement pstmt = null;// 语句对象
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ResultSet rs = null;// 结果集对象
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public DBUtil(String dbname){
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if(dbname!=null&&dbname.trim().length()>0)
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this.dname = dbname;
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}
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public DBUtil(){
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}
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/**
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* 获得连接对象
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*
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* @return 连接对象
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* @throws ClassNotFoundException
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* @throws SQLException
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*/
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public Connection getConnection() {
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try {
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Class.forName(driver);
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con = DriverManager.getConnection(url, username, password);
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} catch (Exception e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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return con;
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}
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/**
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* 关闭三剑客
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*
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* @throws SQLException
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*/
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public void close(ResultSet rs, PreparedStatement pstmt, Connection con) {
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try {
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if (rs != null)
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rs.close();
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if (pstmt != null)
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pstmt.close();
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if (con != null)
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con.close();
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} catch (SQLException e) {
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// TODO: handle exception
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e.printStackTrace();
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}
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}
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/**
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* 执行更新
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*
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* @param sql
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* 传入的预设的 sql语句
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* @param params
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* 问号参数列表
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* @return 影响行数
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*/
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public int execUpdate(String sql, Object[] params) {
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try {
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this.getConnection();// 获得连接对象
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this.pstmt = this.con.prepareStatement(sql);// 获得预设语句对象
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if (params != null) {
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// 设置参数列表
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for (int i = 0; i < params.length; i++) {
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// 因为问号参数的索引是从1开始，所以是i+1，将所有值都转为字符串形式，好让setObject成功运行
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this.pstmt.setObject(i + 1, params[i] + "");
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}
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}
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return this.pstmt.executeUpdate(); // 执行更新，并返回影响行数
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} catch (Exception e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} finally {
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this.close(this.rs, this.pstmt, this.con);
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}
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return 0;
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}
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/**
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* 执行查询sql,返回记录条数
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*
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* @param sql
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* @param params
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* @return
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*/
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public int execSql(String sql, Object[] params) {
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try {
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this.getConnection();// 获得连接对象
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this.pstmt = this.con.prepareStatement(sql);// 获得预设语句对象
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if (params != null) {
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// 设置参数列表
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for (int i = 0; i < params.length; i++) {
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// 因为问号参数的索引是从1开始，所以是i+1，将所有值都转为字符串形式，好让setObject成功运行
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this.pstmt.setObject(i + 1, params[i] + "");
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}
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}
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int i = 0;
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rs = this.pstmt.executeQuery();
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while (rs.next()) {
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i++;
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}
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return i; // 执行更新，并返回影响行数
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} catch (Exception e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} finally {
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this.close(this.rs, this.pstmt, this.con);
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}
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return 0;
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}
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/**
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* 执行查询
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*
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* @param sql
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* 传入的预设的 sql语句
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* @param params
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* 问号参数列表
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* @return 查询后的结果
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*/
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public List<Map<String, Object>> execQuery(String sql, Object[] params) {
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try {
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this.getConnection();// 获得连接对象
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this.pstmt = this.con.prepareStatement(sql);// 获得预设语句对象
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if (params != null) {
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// 设置参数列表
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for (int i = 0; i < params.length; i++) {
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// 因为问号参数的索引是从1开始，所以是i+1，将所有值都转为字符串形式，好让setObject成功运行
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this.pstmt.setObject(i + 1, params[i] + "");
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}
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}
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// 执行查询
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ResultSet rs = pstmt.executeQuery();
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List<Map<String, Object>> al = new ArrayList<Map<String, Object>>();
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// 获得结果集元数据（元数据就是描述数据的数据，比如把表的列类型列名等作为数据）
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ResultSetMetaData rsmd = rs.getMetaData();
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// 获得列的总数
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int columnCount = rsmd.getColumnCount();
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// 遍历结果集
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while (rs.next()) {
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Map<String, Object> hm = new HashMap<String, Object>();
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for (int i = 0; i < columnCount; i++) {
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// 根据列索引取得每一列的列名,索引从1开始
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String columnName = rsmd.getColumnName(i + 1);
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// 根据列名获得列值
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Object columnValue = rs.getObject(columnName);
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// 将列名作为key，列值作为值，放入 hm中，每个 hm相当于一条记录
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hm.put(columnName, columnValue);
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}
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// 将每个 hm添加到al中, al相当于是整个表，每个 hm是里面的一条记录
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al.add(hm);
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}
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return al;
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} catch (Exception e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} finally {
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this.close(this.rs, this.pstmt, this.con);
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}
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return null;
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}
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/**
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* 获取对象的属性，返回键值对
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* @param obj
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* @return
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*/
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public static HashMap<String, Object[]> reflect(Object obj) {
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if (obj == null) return null;
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Field[] fields = obj.getClass().getDeclaredFields();
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String name="";
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Object[] value=new Object[fields.length];
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for (int j = 0; j < fields.length; j++) {
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fields[j].setAccessible(true);
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// 字段名
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name+="`"+fields[j].getName() + "`,";
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// 字段值
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if (fields[j].getType().getName().equals(String.class.getName())) {//String
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try {
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value[j]=(fields[j].get(obj));
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} catch (Exception e) {e.printStackTrace();
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}
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} else if (fields[j].getType().getName().equals(Long.class.getName()) || fields[j].getType().getName().equals("long")) {//int/long
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try {
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value[j]=(fields[j].getLong(obj));
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} catch (Exception e) {e.printStackTrace();}
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}else if (fields[j].getType().getName().equals(Float.class.getName()) || fields[j].getType().getName().equals("float")) {//float/double
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try {
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value[j]=(fields[j].getFloat(obj));
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} catch (Exception e) {e.printStackTrace();}
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}else{// 其他类型。。。
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try {
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value[j]=(fields[j].get(obj));
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} catch (Exception e) {e.printStackTrace();}
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}
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}
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HashMap<String, Object[]> m=new HashMap<>();
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m.put("name", new Object[]{name});
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m.put("value", value);
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return m;
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}
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/**
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* 检查某个表是否存在
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* @param name
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* @return
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*/
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public boolean cktable(String name){
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boolean is = false;
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try {
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this.getConnection();// 获得连接对象
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ResultSet tables = this.con.getMetaData().getTables(null, null, name, null);
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if (tables.next()) is = true;
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} catch (Exception e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} finally {
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this.close(this.rs, this.pstmt, this.con);
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}
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return is;
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}
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}
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