JDBC操作封装

这两天学习了一下jdbc的封装，依据的是下面这篇

http://wenku.baidu.com/link?url=FaFDmQouYkKO24ApATHYmA5QzUcj-UE-7RSSZaBWPqkKB8i13eYw2LGGEsgs_BRyBf7vB_zgB0vBxFXvhXhmLzBfBEPzPCvMvzMvesUwOzW

然后在它的基础上作了修改，简化参数，做了数据类型方面的休整。还不算完全成型，因为对“0”的处理还没有好的解决方案。下面贴出代码。

先贴一个Student实体类

 package com.some.entity;

 import java.io.Serializable;
 import java.sql.Date;

 public class Student implements Serializable {
     private int id;
     private String stuNumber;
     private String stuPassword;
     private String stuName;
     private String stuSex;
     private String stuIdentification;
     private String stuIsGat;
     private String stuPhone;
     private int departmentId;
     private int majorId;
     private String gradeNow;
     private int nationMark;
     private String bithday;// 格式为2015/10/13
     private String address;
     private String politics;

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }

     public String getStuNumber() {
         return stuNumber;
     }

     public void setStuNumber(String stuNumber) {
         this.stuNumber = stuNumber;
     }

     public String getStuPassword() {
         return stuPassword;
     }

     public void setStuPassword(String stuPassword) {
         this.stuPassword = stuPassword;
     }

     public String getStuName() {
         return stuName;
     }

     public void setStuName(String stuName) {
         this.stuName = stuName;
     }

     public String getStuSex() {
         return stuSex;
     }

     public void setStuSex(String stuSex) {
         this.stuSex = stuSex;
     }

     public String getStuIdentification() {
         return stuIdentification;
     }

     public void setStuIdentification(String stuIdentification) {
         this.stuIdentification = stuIdentification;
     }

     public String getStuIsGat() {
         return stuIsGat;
     }

     public void setStuIsGat(String stuIsGat) {
         this.stuIsGat = stuIsGat;
     }

     public String getStuPhone() {
         return stuPhone;
     }

     public void setStuPhone(String stuPhone) {
         this.stuPhone = stuPhone;
     }

     public int getDepartmentId() {
         return departmentId;
     }

     public void setDepartmentId(int departmentId) {
         this.departmentId = departmentId;
     }

     public int getMajorId() {
         return majorId;
     }

     public void setMajorId(int majorId) {
         this.majorId = majorId;
     }

     public String getGradeNow() {
         return gradeNow;
     }

     public void setGradeNow(String gradeNow) {
         this.gradeNow = gradeNow;
     }

     public int getNationMark() {
         return nationMark;
     }

     public void setNationMark(int nationMark) {
         this.nationMark = nationMark;
     }

     public String getBithday() {
         return bithday;
     }

     public void setBithday(String bithday) {
         this.bithday = bithday;
     }

     public String getAddress() {
         return address;
     }

     public void setAddress(String address) {
         this.address = address;
     }

     public String getPolitics() {
         return politics;
     }

     public void setPolitics(String politics) {
         this.politics = politics;
     }
 }

Student.java

然后是数据库连接工具类

 package com.sql.util;

 import java.sql.DriverManager;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;

 import com.mysql.jdbc.PreparedStatement;

 public class DatabaseConnection {
     private static final String driver = "com.mysql.jdbc.Driver";// 数据库驱动
     private static final String url = "jdbc:mysql://localhost:3306/sports_test";// 链接数据库名称
                                                                             // ,localhost替换成域名
     private static final String user = "root";// mysql的登陆用户名
     private static final String password = "1234";// mysql的登陆密码
     private Connection conn = null;

     public DatabaseConnection() throws Exception {// 在构造方法中进行数据库连接
         try {
             Class.forName(driver);//实现静态方法
             this.conn = DriverManager.getConnection(url, user, password);
         } catch (Exception e) {
             e.printStackTrace();
         }
     }

     public Connection getConnection() {
         return this.conn;
     }

     public static void closeConnection(Connection conn) {
         if (conn != null) {
             try {
                 conn.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
     }

     public static void closePreparedStatement(PreparedStatement pstmt) {
         if (pstmt != null) {
             try {
                 pstmt.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
     }

     public static void closeResultSet(ResultSet rs) {
         if (rs != null) {
             try {
                 rs.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
     }
 }

DatabaseConnection.java

顺便贴一个简易hash函数

 package com.change.util;

 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;

 public final class GetHash {
     public static String getMD5(String str){
         String hashedStr=null;
         try{
             MessageDigest md=MessageDigest.getInstance("MD5");
             md.update(str.getBytes());
             byte ss[]=md.digest();
             hashedStr=bytes2String(ss);
         }catch(NoSuchAlgorithmException e){

         }
         return hashedStr;
     }

     private static String bytes2String(byte[] aa){
         String hash="";
         for(int i=0;i<aa.length;i++){
             int temp;
             if(aa[i]<0){
                 temp=256+aa[i];
             }else{
                 temp=aa[i];
             }
             if(temp<16){
                 hash+="0";
             }
             hash+=Integer.toString(temp,16);
         }
         hash=hash.toUpperCase();
         return hash;
     }

 //    public static void main(String[] args) {
 //        String a="123456";
 //        String b="1234567";
 //        String c="fast";
 //        String hashA=GetHash.getMD5(a);
 //        String hashB=GetHash.getMD5(b);
 //        String hashC=GetHash.getMD5(c);
 //        System.out.println(hashA);
 //        System.out.println(hashB);
 //        System.out.println(hashC);
 //        //E10ADC3949BA59ABBE56E057F20F883E
 //        //FCEA920F7412B5DA7BE0CF42B8C93759
 //        //31D4541B8E926A24F0C9B835B68CFDF3
 //    }
 }

GetHash.java

顺便贴一个转换编码的类，有时做下载功能的时候需要用到

 package com.change.util;

 import java.io.UnsupportedEncodingException;

 public class ChangeISO {
     public static String parseGBK(String sIn) {
         if ((sIn == null) || (sIn.equals(""))) {
             return sIn;
         }
         try {
             return new String(sIn.getBytes("GBK"), "ISO-8859-1");
         } catch (UnsupportedEncodingException usex) {
         }
         return sIn;
     }

     public static String parseUTF8(String sIn) {
         if ((sIn == null) || (sIn.equals(""))) {
             return sIn;
         }
         try {
             return new String(sIn.getBytes("UTF-8"), "ISO-8859-1");
         } catch (UnsupportedEncodingException usex) {
         }
         return sIn;
     }
 }

Change

最后就是jdbc增删查改的封装了，有了这个感觉方便很多，不需要像以前一个操作写一大坨函数，我真是太笨了= =

 package com.sql.util;

 import java.security.Timestamp;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.math.BigDecimal;

 import com.change.util.GetHash;
 import com.some.entity.Student;

 /**
  * @see 这个类用于封装sql操作
  */
 public class DatabaseOperator {

     /**
      * @param conn
      *            Connection对象
      * @param obj
      *            vo对象(实体)
      * @param sql
      *            StringBuilder 对象
      * @return List集合
      * @throws Exception
      */

     public static List<?> getSelectList(Connection conn, Object obj,
             StringBuilder sql) {
         int isFirstParameter = 0;
         // 用于装入vo对象中设置属性值的真实属性值
         List<Object> fieldValue = new ArrayList<>();
         // 返回一个list集合，装的是执行过查询的集合，集合resultList装的一般是vo对象
         List<Object> resultList = new ArrayList<>();

         try {
             // 获取对象的所属的类
             Class<?> c = obj.getClass();
             // 取得本类的全部属性
             Field[] f = c.getDeclaredFields();

             for (int i = 0; i < f.length; i++) {
                 String name = f[i].getName();
                 String get = DatabaseOperator.getGos("get", name);

                 // Java 反射机制中 getMethod()和getDeclaredMethod()区别
                 // getMethods()和getDeclaredMethods()区别
                 // 前者只返回共有方法 后者返回全部3种（不包括继承）
                 Method m = c.getDeclaredMethod(get);
                 Object value = m.invoke(obj);
                 if (value != null && value != ""
                         && !String.valueOf(value).equals("0")) {
                     System.out.println(value);
                     // 如果是第一个条件参数，不需要加上and
                     if (isFirstParameter == 0) {
                         sql.append(" " + name + " = ?");
                         isFirstParameter++;
                         // 填入要附加的条件参数
                         fieldValue.add(value);
                     } else {
                         sql.append(" and " + name + " = ?");
                         // 填入要附加的条件参数
                         fieldValue.add(value);
                     }

                 }
             }
             System.out.println(sql);
             PreparedStatement ps = conn.prepareStatement(sql.toString());
             for (int i = 0; i < fieldValue.size(); i++) {
                 // System.out.println(fieldValue.size());
                 // System.out.println(fieldValue.get(i));
                 ps.setObject(i + 1, fieldValue.get(i));
             }
             // 定义结果集
             ResultSet rs = ps.executeQuery();
             while (rs.next()) {
                 Object o = c.newInstance();
                 // f是本类全部属性
                 for (int i = 0; i < f.length; i++) {
                     String name = f[i].getName();
                     // System.out.println(name);
                     String set = DatabaseOperator.getGos("set", name);
                     // System.out.println(set);
                     // 获取类的set方法
                     // System.out.println(f[i].getType());
                     Method m = c.getDeclaredMethod(set, f[i].getType());
                     m.setAccessible(true);
                     // System.out.println(m.getName());
                     Object value = rs.getObject(i + 1);
                     // System.out.println(value + "======");
                     if (value != null) {
                         // String r = f[i].getType().toString();
                         // System.out.println(r);
                         String rsType = value.getClass().getSimpleName();
                         // System.out.println(rsType + "++++");

                         // 判断从数据库读出的数据的数据类型，这里比较奇怪
                         if (rsType.equals("Long")) {
                             m.invoke(o, Integer.parseInt(value.toString()));
                         } else if (rsType.equals("Integer")) {
                             m.invoke(o, value);
                         } else if (rsType.equals("Double")) {
                             m.invoke(o, ((BigDecimal) value).doubleValue());
                         } else if (rsType.equals("Float")) {
                             m.invoke(o, ((BigDecimal) value).floatValue());
                         } else if (rsType.equals("Date")
                                 || rsType.equals("Timestamp")) {
                             // System.out.println("da");
                             if (rsType.equals("Date")) {
                                 m.invoke(o, ((Date) value).toString());
                             } else {
                                 m.invoke(o, ((Timestamp) value).toString());
                             }
                         } else if (rsType.equals("String")) {
                             m.invoke(o, value);
                         } else {
                             // System.out.println("未知");
                         }
                     }
                 }
                 resultList.add(o);
             }
             return resultList;

         } catch (Exception e) {
             e.printStackTrace();
         }

         return resultList;
     }

     /**
      *
      * @param conn
      *            Connection对象
      * @param sql1
      *            StringBuilder 可以增加长度，用于拼接指定的需要插入的列名
      * @param obj
      *            vo对象
      * @return int 0，1执行结果
      * @throws Exception
      */
     public static int doInsert(Connection conn, StringBuilder sql1, Object obj)
             throws Exception {
         Class<?> c = obj.getClass();
         Field[] f = c.getDeclaredFields();
         // StringBuilder 可以增加长度，用于拼接values后面的属性值
         StringBuilder sql2 = new StringBuilder();
         // 用于装入vo对象中设置属性值的真实属性值
         List<Object> fieldValue = new ArrayList<>();

         sql1.append("(");
         sql2.append("values(");
         for (int i = 0; i < f.length; i++) {
             String name = f[i].getName();
             String get = getGos("get", name);
             Method m = c.getDeclaredMethod(get);
             Object value = m.invoke(obj);

             if (value != null && value != ""
                     && !String.valueOf(value).equals("0")) {
                 sql1.append(name + ",");
                 sql2.append("?,");
                 fieldValue.add(value);
             }
         }

         int j = sql1.length() - 1;
         if (sql1.lastIndexOf(",") == j) {
             int start = sql1.length() - 1;
             int end = sql1.length();
             sql1.replace(start, end, "");
         }
         int k = sql2.length() - 1;
         if (sql2.lastIndexOf(",") == k) {
             int start = sql2.length() - 1;
             int end = sql2.length();
             sql2.replace(start, end, "");
         }
         sql1.append(")");
         sql2.append(")");
         StringBuilder sql = sql1.append(sql2);
         System.out.println(sql);

         PreparedStatement ps = conn.prepareStatement(sql.toString());
         // System.out.println(fieldValue.size());
         for (int i = 0; i < fieldValue.size(); i++) {
             // System.out.println(fieldValue.get(i));
             ps.setObject(i + 1, fieldValue.get(i));
         }
         // 执行
         int result = ps.executeUpdate();
         return result;
     }

     /**
      * @param conn
      *            Connection对象
      * @param sql
      *            删除的sql语句(index:delete from student)
      * @param id
      *            删除的主键
      * @return int 0，1执行结果
      */
     public static int doDelete(Connection conn, String sql, String primaryKey,
             int id) {
         sql = sql + " where " + primaryKey + " = ?";
         int result = 0;
         try {
             System.out.println(sql);
             PreparedStatement ps = conn.prepareStatement(sql);
             ps.setInt(1, id);
             result = ps.executeUpdate();
         } catch (SQLException e) {
             e.printStackTrace();
         }
         return result;
     }

     /**
      * @param conn
      *            Connection对象
      * @param sql
      *            要执行的sql语句
      * @param obj
      *            一般是vo对象
      * @param primaryKey
      *            表中的主键， 更新是基于主键更新的
      * @return int 0，1执行结果
      * @throws
      */
     public static int doUpdate(Connection conn, StringBuilder sql, Object obj,
             String primaryKey, Integer id) throws Exception {
         Class<?> c = obj.getClass();
         Field[] f = c.getDeclaredFields();
         // list类型，用于在程序计数传入的属性值
         List<Object> fieldValue = new ArrayList<>();

         sql.append(" set");

         for (int i = 0; i < f.length; i++) {
             String name = f[i].getName();
             String get = getGos("get", name);
             Method m = c.getDeclaredMethod(get);
             Object value = m.invoke(obj);

             int j = name.toLowerCase().indexOf(primaryKey.toLowerCase());
             if (value != null && value != "" && j < 0) {
                 // System.out.println(f[i].getName());
                 sql.append(" " + name + " = ?,");
                 fieldValue.add(value);
             }
         }

         // 去掉最后一个逗号
         int k = sql.length() - 1;
         if (sql.lastIndexOf(",") == k) {
             int start = sql.length() - 1;
             int end = sql.length();
             sql.replace(start, end, "");
         }

         if (id != null) {
             sql.append(" where " + primaryKey + " = ?");
         }

         System.out.println(sql);
         PreparedStatement ps = conn.prepareStatement(sql.toString());
         for (int i = 0; i < fieldValue.size(); i++) {
             // System.out.println(fieldValue.get(i));
             ps.setObject(i + 1, fieldValue.get(i));
         }
         if (id != null) {
             ps.setObject(fieldValue.size() + 1, id);
             System.out.println(id);
         }
         int result = ps.executeUpdate();
         System.out.println(result);
         return result;
     }

     /**
      *  @see getGos是获取get或者set，用于得到一个属性的get和set方法，例如getName()  
      *  @param s:set 或者 get    @param name:属性
      *
      * @return String类型   
      */
     public static String getGos(String s, String name) {
         String str = s + name.substring(0, 1).toUpperCase() + name.substring(1);
         return str;
     }

     public static void main(String[] args) {
         DatabaseConnection dc = null;
         try {
             dc = new DatabaseConnection();
             Connection conn = dc.getConnection();

             // // 查询
             // Student student1 = new Student();
             // // student1.setStuNumber("14020031096");
             // StringBuilder sql1 = new StringBuilder();
             // // sql1.append("select * from student where");
             // sql1.append("select * from student");
             // @SuppressWarnings("unchecked")
             // List<Student> stuList = (List<Student>) DatabaseOperator
             // .getSelectList(conn, student1, sql1);
             // System.out.println(stuList.get(0).getStuNumber());
             // System.out.println(stuList.get(0).getId());
             // for (int i = 0; i < stuList.size(); i++) {
             // System.out.println(stuList.get(i).getStuName());
             // }

             // 增加
             // Student student2 = new Student();
             // student2.setStuName("萌重宝宝");
             // student2.setStuNumber("22222222222");
             // student2.setStuPassword(GetHash.getMD5("123456"));
             // StringBuilder sql2 = new StringBuilder();
             // sql2.append("insert into student");
             // int result=doInsert(conn, sql2, student2);
             // if(result==1){
             // System.out.println("insert成功");
             // }else{
             // System.out.println("insert失败");
             // }

             // 删除
             // String sql3 = "delete from student";
             // String primaryKey = "id";
             // int id = 15458;
             // int result=doDelete(conn, sql3, primaryKey, id);
             // if(result==1){
             // System.out.println("delete成功");
             // }else{
             // System.out.println("delete失败");
             // }

             // 更新
             // Student student4 = new Student();
             // student4.setStuName("萌重儿子");
             // StringBuilder sql4 = new StringBuilder();
             // sql4.append("update student");
             // String primaryKey = "id";
             // int id = 15456;
             // DatabaseOperator.doUpdate(conn, sql4, student4, primaryKey, id);
         } catch (Exception e) {
             e.printStackTrace();
         }

     }
 }

DatabaseOperator

主要是4个函数，还有一个拼接字符串函数，主函数是使用范例。

啦啦啦跑步去