本文主要是介绍Java实现ORM第一个api-FindAll，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
经过几天的业余开发，今天终于到ORM对业务api本身的实现了，首先实现第一个查询的api
老的C#定义如下
因为Java的泛型不纯，所以无法用只带泛型的方式实现api，对查询类的api做了调整，第一个参数要求传入实体对象
首先补充基础方法
反射工具类，用来给实体设置属性值
package LIS.Core.Util;import java.io.File;
import java.lang.reflect.Field;
import java.lang.reflect.Type;
import java.net.URL;
import java.net.URLClassLoader;//反射工具类
public class ReflectUtil {//设置对象指定属性名字的值public static void SetObjValue(Object obj,String name,Object val){try {Class c = obj.getClass();//得到列信息Field declaredField = c.getDeclaredField(name);//布尔的处理if(declaredField.getType()==Boolean.class) {if(val.toString()=="1"){val=Boolean.TRUE;}else if(val.toString()=="0"){val=Boolean.FALSE;}else{val=Boolean.TRUE;}}//布尔的处理else if(declaredField.getType()==boolean.class) {if(val.toString()=="1"){val=true;}else if(val.toString()=="0"){val=false;}else{val=true;}}//布尔的处理else if(declaredField.getType()==int.class) {if(val==null){val=0;}}declaredField.set(obj, val);}catch (Exception ex){ex.printStackTrace();}}/// <summary>/// 用类型全名和程序集全名获得类型/// </summary>/// <param name="typeName">类型全名</param>/// <param name="assemblyName">程序集名</param>/// <returns></returns>public static Class GetType(String typeName, String assemblyName){try {//得到根路径Class<?> clazz = ReflectUtil.class;ClassLoader classLoader = clazz.getClassLoader();URL resourceURL1 = classLoader.getResource("");String bashePath = resourceURL1.getFile();//组装成jar包路径String jarPath=bashePath+assemblyName+".jar";File file = new File(jarPath);if (!file.exists()) {throw new Exception("未能找到"+jarPath+"的文件");}//反射得到类型//自己生成jar包路径URL url = file.toURI().toURL();URL[] urls = new URL[]{url};//加载程序集URLClassLoader loader = new URLClassLoader(urls);//加载类Class c = loader.loadClass(typeName);if(c!=null){return c;}else{throw new Exception("未能构建类型"+typeName);}}catch (Exception ex){ex.printStackTrace();}return null;}
}HashTable转参数列表工具类，把老的HashTable传参数转换为内部ParaDto
package LIS.Core.Util;
import LIS.Core.Dto.ParamDto;
import java.util.List;
import java.util.HashMap;
import java.util.*;import java.util.Hashtable;public class HashToParam {//哈希表得到参数列表public static List<ParamDto> GetParam(Hashtable hs){List<ParamDto> retList=new ArrayList<ParamDto>();Enumeration keys = hs.keys();while(keys.hasMoreElements()) {String str = (String) keys.nextElement();ParamDto dto=new ParamDto();dto.Key=str;dto.Value=hs.get(str);retList.add(dto);}return retList;}
}参数实体，传sql参数用
package LIS.Core.Dto;
//ORM参数对象
public class ParamDto {/// <summary>/// 关键字段名称/// </summary>public Object Key;/// <summary>/// 关键字段值/// </summary>public Object Value;///构造函数public ParamDto(){}//构造函数public ParamDto(Object key, Object value){this.Key = key;this.Value = value;}
}ORM的FindAll实现
package LIS.DAL.ORM.EntityManager;import LIS.Core.Context.ObjectContainer;import java.lang.reflect.Type;
import java.sql.*;
import java.util.List;
import java.util.*;
import LIS.Core.Dto.*;public class EntityManagerImpl implements LIS.DAL.ORM.EntityManager.IEntityManager {/// <summary>/// 存会话信息/// </summary>LIS.Model.Bussiness.Sessions Session=null;/// <summary>/// 开启事务，该方法初始化一个新的事务/// </summary>public void BeginTransaction(){}/// <summary>/// 数据查询/// </summary>/// <typeparam name="T">实体类型</typeparam>/// <param name="model">传入一个空的或者非空的实体对象</param>/// <param name="param">参数哈希表，数据库列名称和值的键值对</param>/// <param name="orderField">排序字段，如RowID ASC,Name DESC</param>/// <param name="pageSize">页面大小。为-1，无条件查询所有数据</param>/// <param name="pageIndex">页码。为-1，无条件查询所有数据</param>/// <returns>对象集合</returns>public <T> List<T> FindAll(T model,Hashtable param, String orderField, int pageSize, int pageIndex){List<T> retList = new ArrayList<T>();//建立连接Connection conn = null;//commandPreparedStatement stmt = null;try {Class c = model.getClass();//转换参数List<ParamDto> para=LIS.Core.Util.HashToParam.GetParam(param);//得到数据库驱动工厂LIS.DAL.ORM.DBUtility.IDbFactory factory= LIS.Core.Context.ObjectContainer.GetTypeObject("LisMianDbFactory");//得到表信息LIS.DAL.ORM.Common.TableInfo tableInfo = LIS.DAL.ORM.Common.ModelToSqlUtil.GetTypeInfo(model);//得到sql语句String sql = LIS.DAL.ORM.Common.ModelToSqlUtil.GetSelectSqlByTableInfo(factory, tableInfo, para, null, null, orderField, false);//连接串，最后的是数据库名称String url = factory.GetConnectionString();//用户String user = factory.GetUserName();//密码String password = factory.GetUserPass();//加载驱动factory.LoadDriver();//数据库连接conn = DriverManager.getConnection(url,user,password);stmt = conn.prepareStatement(sql);//设置数据参数LIS.DAL.ORM.DBUtility.DBParaUtil.SetDBPara(stmt,para);//执行sql得到结果集ResultSet rs = stmt.executeQuery();// 处理查询结果while (rs.next()) {//一行数据T oneRow = (T) c.newInstance();//循环读取列数据放入实体中for(int j=0;j<tableInfo.ColList.size();j++){String ColName=tableInfo.ColList.get(j).Name;Object val=rs.getObject(ColName);//设置属性值LIS.Core.Util.ReflectUtil.SetObjValue(oneRow,ColName,val);}retList.add(oneRow);}// 关闭 ResultSet、Statement 和 Connection 对象rs.close();}catch (Exception ex){ex.printStackTrace();}finally {// 关闭资源try {if (stmt != null){stmt.close();}}catch (Exception se2) {}try {if (conn != null){conn.close();}}catch (Exception se2) {}}return retList;}/// <summary>/// 查询测试/// </summary>public void DBSelectTest(){LIS.DAL.ORM.DBUtility.IDbFactory factory= LIS.Core.Context.ObjectContainer.GetTypeObject("LisMianDbFactory");//连接串，最后的是数据库名称String url = factory.GetConnectionString();//用户String user = factory.GetUserName();//密码String password = factory.GetUserPass();//建立连接Connection conn = null;//commandPreparedStatement stmt = null;try {//加载驱动factory.LoadDriver();conn = DriverManager.getConnection(url,user,password);//编译和执行SQL语句,传输SQL参数查询1997-2000行String sql = "SELECT * FROM dbo.SYS_Form where \"RowID\">? and \"RowID\"<?;";stmt = conn.prepareStatement(sql);stmt.setInt(1,1997);stmt.setInt(2,2000);//结果集ResultSet rs = stmt.executeQuery();// 处理查询结果while (rs.next()) {//取列数据int RowID = rs.getInt("RowID");String CName = rs.getString("CName");String Path = rs.getString("Path");//输出System.out.println(RowID + "\t" + CName + "\t" + Path);}// 关闭 ResultSet、Statement 和 Connection 对象rs.close();}catch (Exception ex) {// 处理 JDBC 异常ex.printStackTrace();}finally {// 关闭资源try {if (stmt != null){stmt.close();}}catch (Exception se2) {}try {if (conn != null){conn.close();}}catch (Exception se2) {}}}/*** Query data object by primary key ID, mainly used for writing business logic with SQL.* The difference between this method and GetById is that it has an internal caching mechanism.* @param <T> Entity type* @param id Object RowID* @return Data object*/public <T> T dolerGet(Object id) {T model=null;model.getClass();//Class<?> type = T.class;//String typeName = type.getSimpleName();//System.out.println(typeName);return null;}///测试SQL生成public <T> void InsertSqlTest1(){try {T model=null;Class c=model.getClass();model=(T)c.newInstance();LIS.DAL.ORM.Common.TableInfo tableInfo = LIS.DAL.ORM.Common.ModelToSqlUtil.GetTypeInfo(model);LIS.DAL.ORM.DBUtility.IDbFactory factory = LIS.Core.Context.ObjectContainer.GetTypeObject("LisMianDbFactory");String sql = LIS.DAL.ORM.Common.ModelToSqlUtil.GetSelectSqlByTableInfo(factory, tableInfo, null, null, null, "", true);System.out.println(sql);}catch (Exception ex){ex.printStackTrace();}}///测试SQL生成public <T> void InsertSqlTest(T model){try {//Type type = EntityManagerImpl.class.getClass().getGenericSuperclass();//Class c = type.getClass();//System.out.println(c.getName());//System.out.println(model.getClass().getName());LIS.DAL.ORM.Common.TableInfo tableInfo = LIS.DAL.ORM.Common.ModelToSqlUtil.GetTypeInfo(model);LIS.DAL.ORM.DBUtility.IDbFactory factory = LIS.Core.Context.ObjectContainer.GetTypeObject("LisMianDbFactory");String sql = LIS.DAL.ORM.Common.ModelToSqlUtil.GetSelectSqlByTableInfo(factory, tableInfo, null, null, null, "", true);System.out.println(sql);}catch (Exception ex){ex.printStackTrace();}}/// <summary>/// 保存对象/// </summary>/// <typeparam name="T">实体类型</typeparam>/// <param name="entity">实体对象</param>/// <returns>影响行数</returns>public <T> int Save(T entity){return 0;}
}实体转Sql的工具类
package LIS.DAL.ORM.Common;
import LIS.Core.CustomAttributes.*;
import LIS.Core.Dto.*;
import LIS.Core.Dto.ParamDto;
import java.util.*;
import java.util.List;
import LIS.DAL.ORM.Common.TableInfo;
import LIS.DAL.ORM.DBUtility.IDbFactory;import java.lang.annotation.Annotation;
import java.lang.reflect.*;
import LIS.DAL.ORM.Common.ColumnInfo;
import LIS.DAL.ORM.Common.TableInfo;
import LIS.Core.Util.ReflectUtil;
import LIS.Core.CustomAttributes.TableAttribute;//通过实体类型得到SQL的工具类
public class ModelToSqlUtil {//通过实体对象得到表信息public static TableInfo GetTypeInfo(Object model) {if (model == null) {return null;}try {//返回的对象TableInfo tableInfo = new TableInfo();Class c = model.getClass();//得到表特性Annotation[] annoList = c.getAnnotations();if (annoList != null && annoList.length > 0) {for (int i = 0; i < annoList.length; i++) {//表特性if (annoList[i] instanceof TableAttribute) {tableInfo.TableInfo = (TableAttribute) annoList[i];}//唯一特性else {tableInfo.UniqueList.add((UniqueAttribute) annoList[i]);}}}//得到列信息Field[] declaredFields = c.getDeclaredFields();for (int i = 0; i < declaredFields.length; i++) {LIS.DAL.ORM.Common.ColumnInfo col = new LIS.DAL.ORM.Common.ColumnInfo();FrekeyAttribute fk = declaredFields[i].getAnnotation(FrekeyAttribute.class);col.FkInfo = fk;col.Name = declaredFields[i].getName();col.ColType = declaredFields[i].getType();col.Value = declaredFields[i].get(model);tableInfo.ColList.add(col);}return tableInfo;} catch (Exception ex) {ex.printStackTrace();}return null;}//通过表信息和参数列表组装查询SQL//factory:驱动工厂//tableInfo:表信息//para:参数//operList:参数对应的操作符列表//linkList:多个参数之间连接的操作符 and or这种//orderBySql:Order By的SQL语句//IsFk:是否组装外键查询的SQLpublic static String GetSelectSqlByTableInfo(IDbFactory factory,TableInfo tableInfo, List<ParamDto> para,List<String> operList,List<String> linkList, String orderBySql,Boolean IsFk){StringBuilder sb=new StringBuilder();sb.append("select ");//是否含有序号列boolean HasSequence=false;boolean HasSeqNum=false;//组装查询列for(int i=0;i<tableInfo.ColList.size();i++){//存列名String columnName = tableInfo.ColList.get(i).Name;if(columnName=="Sequence"){HasSequence=true;}else if(columnName=="SeqNum"){HasSeqNum=true;}//组装查询列if(i==0){sb.append(factory.DealPropertyName(columnName));}else{sb.append(","+factory.DealPropertyName(columnName));}//组装外键查询信息if(IsFk==true&&tableInfo.ColList.get(i).FkInfo!=null) {FrekeyAttribute fkAttr=tableInfo.ColList.get(i).FkInfo;String refTableName=factory.DealTableName(GetTableName(ReflectUtil.GetType("LIS.Model.Entity." + fkAttr.Name(), "LIS.Model")));sb.append("," + "(select " + factory.DealPropertyName(fkAttr.AssociaField()) + " from " + refTableName + " where ti." + factory.DealPropertyName(columnName) + "=" + refTableName + "." + factory.DealPropertyName(fkAttr.RefColumnName()) + ") as " + factory.DealPropertyName(columnName + "_" + fkAttr.Name() + "_" + fkAttr.AssociaField()));//如果有拉取字段1，查询拉取字段if (fkAttr.AssociaField1() != ""){sb.append("," + "(select " + factory.DealPropertyName(fkAttr.AssociaField1()) + " from " + refTableName + " where ti." + factory.DealPropertyName(columnName) + "=" + refTableName + "." + factory.DealPropertyName(fkAttr.RefColumnName()) + ") as " + factory.DealPropertyName(columnName + "_" + fkAttr.Name() + "_" + fkAttr.AssociaField1()));}//如果有拉取字段2，查询拉取字段if (fkAttr.AssociaField2() != ""){sb.append("," + "(select " + factory.DealPropertyName(fkAttr.AssociaField2()) + " from " + refTableName + " where ti." + factory.DealPropertyName(columnName) + "=" + refTableName + "." + factory.DealPropertyName(fkAttr.RefColumnName()) + ") as " + factory.DealPropertyName(columnName + "_" + fkAttr.Name() + "_" + fkAttr.AssociaField2()));}}}sb.append(" from " + factory.DealTableName(tableInfo.TableInfo.Name()) + " ti ");//组装查询参数if(para!=null&¶.size()>0){sb.append(" where ");for(int i=0;i<para.size();i++){String oper="=";if(operList!=null&&operList.size()>i){oper=operList.get(i);}String link="and";if(operList!=null&&operList.size()>i-1){link=operList.get(i-1);}if(i==0) {sb.append(factory.DealPropertyName(para.get(i).Key.toString()) + oper + factory.DealSqlPara(para.get(i).Key.toString()));}else{sb.append(" "+link+" "+factory.DealPropertyName(para.get(i).Key.toString()) + oper + factory.DealSqlPara(para.get(i).Key.toString()));}}}//存组装的排序sqlString strSort = "";//如果传入了排序字段，组装排序语句if (orderBySql != null && orderBySql.length() > 0){//用来存处理的排序串String dealStr = "";//先分割多个排序条件String[] strList = orderBySql.split(",");for (int m = 0; m < strList.length; m++){//分开多个排序条件if (m > 0){dealStr += ",";}//分开字段名称和升降序String[] strSubList = strList[m].split(" ");//处理字段名称dealStr += factory.DealPropertyName(strSubList[0]);//组装处理的串for (int n = 1; n < strSubList.length; n++){dealStr += " " + strSubList[n];}}//组装排序串strSort = " Order By " + dealStr;}else{if (HasSequence){strSort = " Order By " + factory.DealPropertyName("Sequence") + " ASC";}else if (HasSeqNum){strSort = " Order By " + factory.DealPropertyName("SeqNum") + " ASC";}else{strSort = "";}}sb.append(strSort);return sb.toString();}//通过实体类型得到实体表名称private static String GetTableName(Class c){//存表名String strTableName = "";//得到表特性TableAttribute tableInfo = null;//得到表特性Annotation[] annoList = c.getAnnotations();if (annoList != null && annoList.length > 0) {for (int i = 0; i < annoList.length; i++) {//表特性if (annoList[i] instanceof TableAttribute) {tableInfo = (TableAttribute) annoList[i];strTableName=tableInfo.Name();break;}}}return strTableName;}
}数据库驱动工厂，增加得到用户名和密码的方法接口
package LIS.DAL.ORM.DBUtility;//数据驱动层接口，ORM基于此加载驱动和执行SQL
public interface IDbFactory {//得到数据库类型String GetStrDbType();//得到数据库连接串String GetConnectionString();//得到数据库用户名String GetUserName();//得到数据库密码String GetUserPass();//得到返回查询的RowID的SQL语句String GetReturnRowIDSql();//处理表名称，用来适配不同数据库间的属性命名差异String DealTableName(String tableName);//处理属性名字String DealPropertyName(String propertyName);//DealSqlParaString DealSqlPara(String propertyName);//加载驱动void LoadDriver();
}
调用测试，这里引入了阿里的对象转JSON库，fastjson
package com.company;
//import org.apache.commons.configuration.ConfigurationException;
//import org.apache.commons.configuration.PropertiesConfiguration;
import LIS.Model.Entity.SYSForm;
import LIS.Model.Entity.SYSUser;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;
import java.net.URL;
import java.util.List;
import java.util.HashMap;
import java.util.*;
import com.alibaba.fastjson.*;public class Main {public static void main(String[] args) {//用容器的配置xml初始化容器LIS.Core.Context.ObjectContainer.InitIoc();//ORM通过容器取数据库驱动工厂LIS.DAL.ORM.EntityManager.EntityManagerImpl orm=new LIS.DAL.ORM.EntityManager.EntityManagerImpl();//执行查询测试orm.DBSelectTest();//测试通过实体得到SQL语句orm.InsertSqlTest(new SYSForm());orm.InsertSqlTest(new SYSUser());//调用ORM的FindAll测试Hashtable hs=new Hashtable();hs.put("Code","QC");List<SYSForm> formList=orm.FindAll(new SYSForm(),hs,"RowID desc",-1,-1);Object json=JSONObject.toJSON(formList);System.out.println("查询的LIST数据:"+json.toString());}
}测试结果
把依赖的不稳定搞定后就快多了，轻松加愉快，哈哈。不过发现泛型不如C#强，方法不支持默认参数，尤其是方法不支持默认参数这个真不像一个现代语言，总体使用语法特性方面和工程依赖方面和IDE体验和C#比差多了，末日黄花喽，官方闭源，语法古老
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