福建建设部网站,定制家具设计师培训,如何做百度搜索推广,襄阳市网站建设本文将封装JDBC的操作#xff0c;实现简单的ORM框架#xff0c;提供3种风格的api来给用户使用#xff08;1.原生jdbcSqlBuilder#xff1b;2.类似jpa和mp的#xff1b;3.注解接口方法#xff09; 代码仓库#xff1a;malred/IFullORM
1. 原生JDBCsql构建器
第一步实现简单的ORM框架提供3种风格的api来给用户使用1.原生jdbcSqlBuilder2.类似jpa和mp的3.注解接口方法 代码仓库malred/IFullORM
1. 原生JDBCsql构建器
第一步 封装jdbc
这个框架的重点是将jdbc等操作隐藏到框架内部从而让用户更轻松地实现sql操作JDBC的部分就粗略地过一下代码
JDBCUtils package org.malred.utils;import java.sql.*;public class JDBCUtils {static String url;// defaultUrldbName - urlstatic String defaultUrl jdbc:mysql://localhost:3306/;static String dbName;static String driverName;static String defaultDriverName com.mysql.cj.jdbc.Driver;static String user;static String password;public static void setDataSource(String url, String driverName, String user, String password) {JDBCUtils.url url;JDBCUtils.driverName driverName;JDBCUtils.user user;JDBCUtils.password password;}public static void setDataSource(String dbName, String user, String password) {JDBCUtils.url defaultUrl dbName;JDBCUtils.driverName defaultDriverName;JDBCUtils.user user;JDBCUtils.password password;}public static void setUrl(String url) {JDBCUtils.url url;}public static void setDriverName(String driverName) {JDBCUtils.driverName driverName;}public static void setUser(String user) {JDBCUtils.user user;}public static void setPassword(String password) {JDBCUtils.password password;}public static Connection getConn() {try {// 四要素 - 让用户传
// String url jdbc:mysql://localhost:3306/test;
// String user root;
// String password root;
// String driverName com.mysql.cj.jdbc.Driver;//实例化驱动Class.forName(driverName);//获取连接Connection conn DriverManager.getConnection(url, user, password);return conn;} catch (Exception e) {e.printStackTrace();return null;}}public static void close(Connection conn, PreparedStatement ps) {try {if (conn ! null) conn.close();if (ps ! null) ps.close();} catch (SQLException e) {e.printStackTrace();}}public static void close(Connection conn) {try {if (conn ! null) conn.close();} catch (SQLException e) {e.printStackTrace();}}public static void close(PreparedStatement ps) {try {if (ps ! null) ps.close();} catch (SQLException e) {e.printStackTrace();}}public static void close(Connection conn, PreparedStatement ps, ResultSet rs) {try {if (conn ! null) conn.close();if (ps ! null) ps.close();if (rs ! null) rs.close();} catch (Exception e) {e.printStackTrace();}}
}
Operate 该部分代码来源于JDBC3实现通用的增删改查方法_如何将增删改查方法抽成公共方法-CSDN博客
public class Operate {//通用的更新数据库的方法insert,update,delete 语句时public static int update(String sql) throws SQLException {//1、获取连接Connection conn JDBCUtils.getConn();//2、获取 Statement 对象这个对象是用来给服务器传 sql 并执行 sqlStatement st conn.createStatement();//3、执行 sqlint len st.executeUpdate(sql);//4、释放资源JDBCUtils.close(conn, (PreparedStatement) st);return len;}// 通用的更新数据库的方法insert,update,delete 语句允许 sql 带?public static int update(String sql, Object... args) throws SQLException {Connection conn JDBCUtils.getConn();int len update(conn, sql, args);JDBCUtils.close(conn);return len;}// 通用的更新数据库的方法insert,update,delete 语句允许 sql 带?public static int update(Connection conn, String sql, Object... args) throws SQLException {//2、获取 PreparedStatement 对象这个对象是用来 sql 进行预编译PreparedStatement pst conn.prepareStatement(sql);//3、设置 sql 中的?if (args ! null args.length 0) {//数组的下标是从 0 开始的编号是 1 开始for (int i 0; i args.length; i) {pst.setObject(i 1, args[i]);}}//4、执行 sqlint len pst.executeUpdate();//5、释放资源JDBCUtils.close(pst);return len;}//通用的查询方法之一查询一行即一个对象/*** 执行查询操作的 SQL 语句SQL 可以带参数(?)** param clazz Class 查询的结果需要封装的实体的 Class 类型例如学生 Student商品 Goods,订单 Order* param sql String 执行查询操作的 SQL 语句* param args Object... 对应的每个?设置的值顺序要与?对应* return T 封装了查询结果的实体* throws Exception*/public static T T get(ClassT clazz, String sql, Object... args) throws Exception {//1、注册驱动//2、获取连接Connection conn JDBCUtils.getConn();//3、对 sql 进行预编译PreparedStatement pst conn.prepareStatement(sql);//4、设置if (args ! null args.length 0) {//数组的下标是从 0 开始的编号是 1 开始for (int i 0; i args.length; i) {pst.setObject(i 1, args[i]);}}//5、查询ResultSet rs pst.executeQuery();//获取查询的结果集的元数据信息ResultSetMetaData rsmd rs.getMetaData();//这是查询的结果集中一共有几列int count rsmd.getColumnCount();T t clazz.newInstance();//要求这个 Javabean 类型必须有无参构造while (rs.next()) {/** 问题* 1sql 语句中查询了几列每一列是什么属性* 2怎么把这个值设置到 Javabean 的属性中*///循环每一行有几列for (int i 0; i count; i) {//第几列的名称// String columnName rsmd.getColumnName(i1);//如果 sql 中没有取别名那么就是列名如果有别名返回的是别名String fieldName rsmd.getColumnLabel(i 1);//该列的值// Object value rs.getObject(columnName);Object value rs.getObject(fieldName);//设置 obj 对象的某个属性中Field field clazz.getDeclaredField(fieldName);//JavaBean 的属性名field.setAccessible(true);field.set(t, value);}}//5、释放资源JDBCUtils.close(conn, pst, rs);return t;}//通用的查询方法之二查询多行即多个对象//ClassT clazz用来创建实例对象获取对象的属性并设置属性值/*** 执行查询操作的 SQL 语句SQL 可以带参数(?)** param clazz Class 查询的结果需要封装的实体的 Class 类型例如学生 Student商品 Goods,订单 Order* param sql String 执行查询操作的 SQL 语句* param args Object... 对应的每个?设置的值顺序要与?对应* return ArrayListT 封装了查询结果的集合* throws Exception*/public static T ArrayListT getList(ClassT clazz, String sql, Object... args) throws Exception {//1、注册驱动不用了//2、获取连接Connection conn JDBCUtils.getConn();//3、对 sql 进行预编译PreparedStatement pst conn.prepareStatement(sql);//4、对进行设置值if (args ! null args.length 0) {for (int i 0; i args.length; i) {pst.setObject(i 1, args[i]);}}//5、执行 sqlResultSet rs pst.executeQuery();//获取结果集的元数据ResultSetMetaData metaData rs.getMetaData();//获取结果中总列数int count metaData.getColumnCount();//创建集合对象ArrayListT list new ArrayListT();while (rs.next()) {//遍历的行//1、每一行是一个对象T obj clazz.newInstance();//2、每一行有很多列//for 的作用是为 obj 对象的每一个属性设置值for (int i 0; i count; i) {//(1)每一列的名称String fieldName metaData.getColumnLabel(i 1);//获取第几列的名称如果有别名获取别名如果没有别名获取列名//(2)每一列的值Object value rs.getObject(i 1);//获取第几列的值//(3)获取属性对象Field field clazz.getDeclaredField(fieldName);//(4)设置可见性field.setAccessible(true);//(5)设置属性值field.set(obj, value);}//3、把 obj 对象放到集合中list.add(obj);}//6、释放资源JDBCUtils.close(conn, pst, rs);//7、返回结果return list;}//通用的查询方法之三查询单个值//单值select max(salary) from employee; 一行一列//select count(*) from t_goods; 一共几件商品public static Object getValue(String sql, Object... args) throws Exception {//2、获取连接Connection conn JDBCUtils.getConn();//3、对 sql 进行预编译PreparedStatement pst conn.prepareStatement(sql);//4、对进行设置值if (args ! null args.length 0) {for (int i 0; i args.length; i) {pst.setObject(i 1, args[i]);}}//5、执行 sqlResultSet rs pst.executeQuery();Object value null;if (rs.next()) {//一行value rs.getObject(1);//一列}//6、释放资源JDBCUtils.close(conn, pst, rs);return value;}
}
第二步 sql构建器 SqlBuilder 类
我们将sql语句拆分为小段然后定义单独的方法一个一个地拼接sql语句链式调用最后通过一个方法获取类内部存放的sql语句 类的一些字段
public class SqlBuilder {String sql;String tbName;// 表名String joinTb;// 连接的表的名称private SqlBuilder() {}public static SqlBuilder build() {return new SqlBuilder();}public String sql() {return this.sql;}// 自定义基础sqlpublic SqlBuilder base(String U_sql) {this.sql U_sql;return this;}public SqlBuilder tbName(String tbName) {this.tbName tbName;return this;}
}
select
select可以拆分为 select x,x,x from tbName join joinTb on tbName.xjoinTb.x where tbName.x? 为的部分由用户调用原生接口时传入参数jdbc填充tbName和joinTb也需要用户传入传入后在构建器内部保存这两个值x是用户构建sql时要传入的代表参数字段的名称会写死在sql里 public SqlBuilder select(String tbName, String... columns) {this.sql select ;for (int i 0; i columns.length; i) {if (i columns.length - 1) {this.sql columns[i] ;break;}this.sql columns[i] , ;}this.sql from tbName;return this;}public SqlBuilder select(String[] columns) {this.sql select ;for (int i 0; i columns.length; i) {if (i columns.length - 1) {this.sql columns[i] ;break;}this.sql columns[i] , ;}this.sql from tbName;return this;}public SqlBuilder select(String tbName) {this.sql select * from tbName;return this;}public SqlBuilder select() {this.sql select * from tbName;return this;}public SqlBuilder join(SqlJoinType type, String joinTb) {this.joinTb joinTb;sql Common.JOIN_TYPE[type.ordinal()] join joinTb;return this;}public SqlBuilder on(String in_column, SqlCompareIdentity identity, String out_column) {sql on joinTb . in_column Common.Compares[identity.ordinal()] tbName . out_column;return this;}public SqlBuilder count(String tbName) {this.sql select count(*) from tbName;return this;}public SqlBuilder count() {this.sql select count(*) from tbName;return this;}public SqlBuilder where(String column, SqlCompareIdentity join) {if (!sql.contains(where)) {this.sql where column Common.Compares[join.ordinal()] ? ;return this;}this.sql and column Common.Compares[join.ordinal()] ? ;return this;}
update
update可以拆分为 update tbName set x?,x? where x? public SqlBuilder update(String tbName, String... columns) {this.sql update tbName set ;for (int i 0; i columns.length; i) {if (i columns.length - 1) {this.sql columns[i] ? ;break;}this.sql columns[i] ?,;}return this;}public SqlBuilder update(String[] columns) {this.sql update tbName set ;for (int i 0; i columns.length; i) {if (i columns.length - 1) {this.sql columns[i] ? ;break;}this.sql columns[i] ?,;}return this;}
delete
delete delete from tbName where x ? public SqlBuilder delete(String tbName) {sql delete from tbName;return this;}public SqlBuilder delete() {sql delete from tbName;return this;}
insert
insert insert into tbName(x,x,x) values (?,?,?), (?,?,?) public SqlBuilder insert(String tbName, String... params) {sql insert into tbName;sql (;for (int i 0; i params.length; i) {if (i params.length - 1) {sql params[i] ) ;break;}sql params[i] ,;}sql values (;for (int i 0; i params.length; i) {if (i params.length - 1) {sql ?);break;}sql ?,;}return this;}public SqlBuilder insert(String[] params) {sql insert into tbName;sql (;for (int i 0; i params.length; i) {if (i params.length - 1) {sql params[i] ) ;break;}sql params[i] ,;}sql values (;for (int i 0; i params.length; i) {if (i params.length - 1) {sql ?);break;}sql ?,;}return this;}
测试sqlBuilder
public class t {Beforepublic void before() {// 设置数据库属性JDBCUtils.setDataSource(jdbc:mysql://localhost:3306/test,com.mysql.cj.jdbc.Driver, root, root);}// sqlbuilderjdbc封装Testpublic void testSelectBuild() {String sql SqlBuilder.build().select(tb_user).where(id, SqlCompareIdentity.NE).sql();System.out.println(sql);String sql_cols SqlBuilder.build().select(tb_user, username, gender, addr).where(id, SqlCompareIdentity.NE).sql();System.out.println(sql_cols);String sql_cols_option2 SqlBuilder.build().select(tb_user, username, gender, addr).where(id, SqlCompareIdentity.NE).where(password, SqlCompareIdentity.NE).sql();System.out.println(sql_cols_option2);String sql_count SqlBuilder.build().count(tb_user).where(id, SqlCompareIdentity.GT).sql();System.out.println(sql_count);}Testpublic void testSelectBuildTbName() {// 直接设置build的tbName,然后使用不需要tbName的方法来构建String sql1 SqlBuilder.build().tbName(tb_user).select().where(id, SqlCompareIdentity.NE).sql();System.out.println(sql1);String sql_cols1 SqlBuilder.build().tbName(tb_user).select(new String[]{username, gender, addr}).where(id, SqlCompareIdentity.NE).sql();System.out.println(sql_cols1);String sql_cols_option21 SqlBuilder.build().tbName(tb_user).select(new String[]{username, gender, addr}).where(id, SqlCompareIdentity.NE).where(password, SqlCompareIdentity.NE).sql();System.out.println(sql_cols_option21);String sql_count1 SqlBuilder.build().tbName(tb_user).count().where(id, SqlCompareIdentity.GT).sql();System.out.println(sql_count1);String sql_join SqlBuilder.build().tbName(tb_user).select().join(SqlJoinType.INNER, tb_product).on(id, SqlCompareIdentity.EQ, id).where(tb_user.id, SqlCompareIdentity.EQ).sql();System.out.println(sql_join);}Testpublic void testUpdateBuild() {String sql SqlBuilder.build().update(tb_user, password, username).where(id, SqlCompareIdentity.EQ).sql();System.out.println(sql);String sql_no_tbname SqlBuilder.build().tbName(tb_user).update(new String[]{password, username}).where(id, SqlCompareIdentity.EQ).sql();System.out.println(sql_no_tbname);}Testpublic void testInsertBuild() {String sql SqlBuilder.build().insert(tb_user, username, password, addr, gender).sql();System.out.println(sql);}Testpublic void testInsertBuildTbName() {String sql SqlBuilder.build().tbName(tb_user).insert(new String[]{username, password, addr, gender}).sql();System.out.println(sql);}Testpublic void testDeleteBuild() {String sql_tb SqlBuilder.build().tbName(tb_user).delete().where(id, SqlCompareIdentity.EQ).sql();System.out.println(sql_tb);String sql SqlBuilder.build().delete(tb_user).where(id, SqlCompareIdentity.EQ).sql();System.out.println(sql);}
}
第三步 使用原生接口sql构建器执行crud Beforepublic void before() {// 设置数据库属性JDBCUtils.setDataSource(jdbc:mysql://localhost:3306/test,com.mysql.cj.jdbc.Driver, root, root);}Testpublic void testSelectMulti() throws Exception {ArrayListTbUser list;String sql SqlBuilder.build().select(tb_user).where(id, SqlCompareIdentity.NE).sql();list Operate.getList(TbUser.class, sql, 1);System.out.println(list);String sql_cols SqlBuilder.build().select(tb_user, username, gender, addr).where(id, SqlCompareIdentity.NE).sql();list Operate.getList(TbUser.class, sql_cols, 1);System.out.println(list);String sql_cols_option2 SqlBuilder.build().select(tb_user, username, gender, addr).where(id, SqlCompareIdentity.NE).where(gender, SqlCompareIdentity.NE).sql();list Operate.getList(TbUser.class, sql_cols_option2, 1, 男);System.out.println(list);String sql_count SqlBuilder.build().count(tb_user).where(id, SqlCompareIdentity.GT).sql();Long cnt (Long) Operate.getValue(sql_count, 3);System.out.println(cnt);}Testpublic void testUpdate() throws SQLException {int cnt 0;String sql SqlBuilder.build().update(tb_user, password, username).where(id, SqlCompareIdentity.EQ).sql();cnt Operate.update(sql, O, t50, 13);System.out.println(影响了 cnt 条数据);String sql_no_tbname SqlBuilder.build().tbName(tb_user).update(new String[]{password, username}).where(id, SqlCompareIdentity.EQ).sql();cnt Operate.update(sql_no_tbname, Obu, t50123, 13);System.out.println(影响了 cnt 条数据);}Testpublic void testInsert() throws SQLException {int count 0;String sql SqlBuilder.build().insert(tb_user, username, password, addr, gender).sql();count Operate.update(sql, name, pass, cn, 男);System.out.println(影响了 count 条数据);}Testpublic void testDelete() throws SQLException {int cnt 0;String sql_tb SqlBuilder.build().tbName(tb_user).delete().where(id, SqlCompareIdentity.EQ).sql();cnt Operate.update(sql_tb, 219);System.out.println(影响了 cnt 条数据);}
这里的SqlCompareIdentity是为了方便管理把一些比较关键字放到枚举里然后在commons类里定义数组根据enum的索引从数组里拿比较运算符来拼接
SqlCompareIdentity public enum SqlCompareIdentity {GT,// GE,// LT, // LE,// EQ, // NE, // !
}
Common public class Common {public static final String[] Compares new String[]{, , , , , !, like, in};// baseCRUD方法的名称public static final String[] JOIN_TYPE new String[]{left,right,full,inner,left outer,right outer};
}
SqlJoinType public enum SqlJoinType {// left,right,full,inner,left outer,right outerLEFT,RIGHT,FULL,INNER,LO,RO
}
2. 创建BaseCRUDRepository实现动态代理
思路BaseCRUDRepositoryT里定义基本curd方法select方法的返回值由传入的泛型决定因为方法名是死的所以可以通过方法名来判断是哪个方法我们可以在动态代理里根据不同方法提供不同的实现用户只需要创建接口继承BaseCRUDRepository就可以使用这些方法 Repository是一个注解主要是指定数据库表名用的 package org.malred.annotations;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;Target(ElementType.TYPE)
Retention(RetentionPolicy.RUNTIME)
public interface Repository {String value(); // 表名
}
Operate 这里的type1是执行jdbc方法需要的实体类类型本来想通过泛型拿到但是好像java不能反射获取类的泛型 // 定义在Operate类里public static T T getMapper(Class? mapperClass, Class? type1) {// 使用JDK动态代理为Dao接口生成代理对象,并返回Object proxyInstance Proxy.newProxyInstance(Operate.class.getClassLoader(), new Class[]{mapperClass}, new InvocationHandler() {Overridepublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable {// 拿到表名Repository annotation mapperClass.getAnnotation(Repository.class);String tbName annotation.value();// 拼装sql
// String sql (String) Common.DefaultCRUDSql.get(method.getName());
// System.out.println(sql);String sql ;// 默认CRUD接口的代理方法switch (method.getName()) {case findAll: {sql SqlBuilder.build().tbName(tbName).select().sql();System.out.println(执行findAll方法);System.out.println(当前执行的sql语句: sql);return Operate.getList(type1, sql);}case findById: {sql SqlBuilder.build().tbName(tbName).select().where(id, SqlCompareIdentity.EQ).sql();System.out.println(执行findById方法);System.out.println(当前执行的sql语句: sql);return Operate.get(type1, sql, args);}case update: {ParseClazz parseClazz parseObjectArgs(args);String[] paramNames new String[parseClazz.params.keySet().size()];for (int i 0; i parseClazz.params.keySet().toArray().length; i) {paramNames[i] parseClazz.params.keySet().toArray()[i].toString();}sql SqlBuilder.build().update(tbName, paramNames).where(parseClazz.idName, SqlCompareIdentity.EQ).sql();System.out.println(执行update方法);System.out.println(当前执行的sql语句: sql);String[] paramVals new String[parseClazz.params.values().size() 1];for (int i 0; i parseClazz.params.values().toArray().length; i) {paramVals[i] parseClazz.params.values().toArray()[i].toString();
// System.out.println(paramVals[i]);}paramVals[paramVals.length - 1] parseClazz.idVal.toString();return Operate.update(sql, paramVals);}case insert: {ParseClazz parseClazz parseObjectArgs(args);String[] paramNames new String[parseClazz.params.keySet().size()];for (int i 0; i parseClazz.params.keySet().toArray().length; i) {paramNames[i] parseClazz.params.keySet().toArray()[i].toString();}sql SqlBuilder.build().tbName(tbName).insert(paramNames).sql();System.out.println(执行insert方法);System.out.println(当前执行的sql语句: sql);String[] paramVals new String[parseClazz.params.values().size()];for (int i 0; i parseClazz.params.values().toArray().length; i) {paramVals[i] parseClazz.params.values().toArray()[i].toString();
// System.out.println(paramVals[i]);}return update(sql, paramVals);}case delete: {sql SqlBuilder.build().tbName(tbName).delete().where(id, SqlCompareIdentity.EQ).sql();System.out.println(执行delete方法);System.out.println(当前执行的sql语句: sql);return update(sql, args[0]);}}return null;}});return (T) proxyInstance;}
测试 // 基本CRUD接口的代理实现测试Testpublic void testSelectProxy() {UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);
// UserRepository mapper Operate.getMapper(UserRepository.class);ListTbUser all mapper.findAll();System.out.println(all);TbUser one mapper.findById(1);System.out.println(one);}Testpublic void testUpdateProxy() {int cnt 0;
// UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);UserRepository mapper Operate.getMapper(UserRepository.class);cnt mapper.update(new TbUser(212, ema1n, s1sap, 女, null));System.out.println(影响了 cnt 条数据);// cnt mapper.update(new TbUser(211, name, pass, null, null));
// System.out.println(影响了 cnt 条数据);}Testpublic void testInsertProxy() {int cnt 0;
// UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);UserRepository mapper Operate.getMapper(UserRepository.class);cnt mapper.insert(new TbUser(0, eman, ssap, null, null));System.out.println(影响了 cnt 条数据);}Testpublic void testDeleteProxy() {int cnt 0;UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);cnt mapper.delete(223);System.out.println(影响了 cnt 条数据);}
3. 注解接口方法
思路依然是走动态代理只是sql的获取不再是框架构建而是用户在注解中定义框架只是把值填充这里我们需要注意如果是第二种方法和注解的混用会有一个类型问题 这个问题就是如果传入了type1那么所有被代理的方法如果都用type1作为调用jdbc时传入的实体类型就无法使用其他类型无法查询并封装到其他类型而我们的解决方法是注解的方法就根据注解方法的返回值来传递实体类型base方法就用type1 public static T T getMapper(Class? mapperClass, Class? type1) {// 使用JDK动态代理为Dao接口生成代理对象,并返回Object proxyInstance Proxy.newProxyInstance(Operate.class.getClassLoader(), new Class[]{mapperClass}, new InvocationHandler() {Overridepublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable {// 用户定义的方法的返回类型Class? type null;//获取方法的返回值类型Type genericReturnType method.getGenericReturnType();if (!method.getName().equals(findAll) !method.getName().equals(findById)) {if (genericReturnType instanceof ParameterizedType) {Type[] actualTypeArguments ((ParameterizedType) genericReturnType).getActualTypeArguments();for (Type parameterType : actualTypeArguments) {System.out.println(parameterType);type (Class?) parameterType;}} else {type (Class?) genericReturnType;}}// 拿到表名Repository annotation mapperClass.getAnnotation(Repository.class);String tbName annotation.value();// 拼装sql
// String sql (String) Common.DefaultCRUDSql.get(method.getName());
// System.out.println(sql);String sql ;// 默认CRUD接口的代理方法switch (method.getName()) {case findAll: {sql SqlBuilder.build().tbName(tbName).select().sql();System.out.println(执行findAll方法);System.out.println(当前执行的sql语句: sql);return Operate.getList(type1, sql);}case findById: {sql SqlBuilder.build().tbName(tbName).select().where(id, SqlCompareIdentity.EQ).sql();System.out.println(执行findById方法);System.out.println(当前执行的sql语句: sql);return Operate.get(type1, sql, args);}case update: {ParseClazz parseClazz parseObjectArgs(args);String[] paramNames new String[parseClazz.params.keySet().size()];for (int i 0; i parseClazz.params.keySet().toArray().length; i) {paramNames[i] parseClazz.params.keySet().toArray()[i].toString();}sql SqlBuilder.build().update(tbName, paramNames).where(parseClazz.idName, SqlCompareIdentity.EQ).sql();System.out.println(执行update方法);System.out.println(当前执行的sql语句: sql);String[] paramVals new String[parseClazz.params.values().size() 1];for (int i 0; i parseClazz.params.values().toArray().length; i) {paramVals[i] parseClazz.params.values().toArray()[i].toString();
// System.out.println(paramVals[i]);}paramVals[paramVals.length - 1] parseClazz.idVal.toString();return Operate.update(sql, paramVals);}case insert: {ParseClazz parseClazz parseObjectArgs(args);String[] paramNames new String[parseClazz.params.keySet().size()];for (int i 0; i parseClazz.params.keySet().toArray().length; i) {paramNames[i] parseClazz.params.keySet().toArray()[i].toString();}sql SqlBuilder.build().tbName(tbName).insert(paramNames).sql();System.out.println(执行insert方法);System.out.println(当前执行的sql语句: sql);String[] paramVals new String[parseClazz.params.values().size()];for (int i 0; i parseClazz.params.values().toArray().length; i) {paramVals[i] parseClazz.params.values().toArray()[i].toString();
// System.out.println(paramVals[i]);}return update(sql, paramVals);}case delete: {sql SqlBuilder.build().tbName(tbName).delete().where(id, SqlCompareIdentity.EQ).sql();System.out.println(执行delete方法);System.out.println(当前执行的sql语句: sql);return update(sql, args[0]);}}// 如果都不是上面的,就是用户自己定义的if (method.isAnnotationPresent(Select.class)) {Select selectAnno method.getAnnotation(Select.class);sql selectAnno.value();// 判断是查询单个还是多个(返回值类型是List之类的吗)// 这里只是简单判断一下
// Type genericReturnType method.getGenericReturnType();// 判断是否进行了泛型类型参数化(是否有泛型)if (genericReturnType instanceof ParameterizedType) {
// if (x instanceof Collection ? ){
// }
// if (x instanceof Map?,?){
// }return Operate.getList(type, sql, args);}return Operate.get(type, sql, args);}if (method.isAnnotationPresent(Update.class)) {Update anno method.getAnnotation(Update.class);sql anno.value();return update(sql, args);}if (method.isAnnotationPresent(Delete.class)) {Delete anno method.getAnnotation(Delete.class);sql anno.value();return update(sql, args);}if (method.isAnnotationPresent(Insert.class)) {Insert anno method.getAnnotation(Insert.class);sql anno.value();return update(sql, args);}// 返回值return null;}});return (T) proxyInstance;}测试 // 用户定义的注解的代理实现测试Testpublic void testSelectAnnotation() {UserRepository mapper Operate.getMapper(UserRepository.class);
// UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);TbUser user mapper.selectOneByUsername(张三);System.out.println(user);ListTbUser tbUsers mapper.selectOneByNEPassword(456);for (TbUser tbUser : tbUsers) {System.out.println(tbUser);}// 和因为在代理时写死传入的返回值类型,这里只能重新创建代理// 根据接口方法的返回值获取泛型类型,动态判断返回类型
// UserRepository puMapper
// Operate.getMapper(UserRepository.class, ProductAndUser.class);
// UserRepository puMapper Operate.getMapper(UserRepository.class);ListProductAndUser userAndProductJoin mapper.findUserAndProductJoin(7);System.out.println(userAndProductJoin);}Testpublic void testUpdateAnnotation() {
// UserRepository mapper
// Operate.getMapper(UserRepository.class, TbUser.class);UserRepository mapper Operate.getMapper(UserRepository.class);int cnt mapper.uptUser(哇哈哈1, 14);System.out.println(影响了 cnt 条数据);}Testpublic void testDeleteAnnotation() {
// UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);UserRepository mapper Operate.getMapper(UserRepository.class);int cnt mapper.delUser(218, tpass);System.out.println(影响了 cnt 条数据);}Testpublic void testInsertAnnotation() {
// UserRepository mapper Operate.getMapper(UserRepository.class, TbUser.class);UserRepository mapper Operate.getMapper(UserRepository.class);int cnt mapper.addUser(tttt, tpass, tttt2, tpass2);System.out.println(影响了 cnt 条数据);}
下一步 接口代理的selectBy实体类属性名方法
思路实体类加上注解指定表名Operator的static里扫描注解并将key-表名val-扫到的类注入到一个map代理方法里通过Repository里的表名和map里的匹配拿到实体类拼接字符串selectByxxx放入list当执行方法进入代理就判断是否在list中包含然后实现代理逻辑
