需求

因工作需求，需要根据用户的数据权限，来查询并展示相应的数据，那么就需要动态拦截sql,在根据用户权限做相应的处理，因此需要一个通用拦截器，并以注解实现。该文只做查询拦截，如有其他需求，可根据工作做相应更改。

步骤一

该注解是方法级，因此需要注解在dao层方法上，如有需要也可更改为类级

注解：

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Documented
// 指名数据库查询方法需要和权限挂钩
public @interface Permission {
}

步骤二

定义拦截器实现接口重写其intercept方法

@Intercepts({
//        @Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})
//        @Signature( type = Executor.class, method = "update",args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query",args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}),
        @Signature(type = Executor.class, method = "query",args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class})
})
@Component
public class PermissionInterceptor implements Interceptor {
	@Override
    public Object intercept(Invocation invocation) throws Throwable {
    }
}

步骤三

拿到所有查询sql请求，并得到相应的statement

@Intercepts({
//        @Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})
//        @Signature( type = Executor.class, method = "update",args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query",args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}),
        @Signature(type = Executor.class, method = "query",args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class})
})
@Component
public class PermissionInterceptor implements Interceptor {
	@Override
    public Object intercept(Invocation invocation) throws Throwable {
     String processSql = ExecutorPluginUtils.getSqlByInvocation(invocation);
        // 执行自定义修改sql操作
        // 获取sql
        String sql2Reset = processSql;
        Statement statement = CCJSqlParserUtil.parse(processSql);
        MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
    }
}

步骤四

如果后端未用分页，则这步可以省略在项目启动类下完成该配置

		 //得到spring上下文
		 ConfigurableApplicationContext run = SpringApplication.run(Application.class, args);
		 Interceptor permissionInterceptor = (Interceptor) run.getBean("permissionInterceptor");
		 //这种方式添加mybatis拦截器保证在pageHelper前执行
		 run.getBean(SqlSessionFactory.class).getConfiguration().addInterceptor(permissionInterceptor);

步骤五

工具类

package com.ydy.common.utils;
import com.ydy.common.annotation.Permission;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.mapping.SqlSource;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.reflection.DefaultReflectorFactory;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.Objects;
public class ExecutorPluginUtils {
    /**
     * 获取sql语句
     * @param invocation
     * @return
     */
    public static String getSqlByInvocation(Invocation invocation) {
        final Object[] args = invocation.getArgs();
        MappedStatement ms = (MappedStatement) args[0];
        Object parameterObject = args[1];
        BoundSql boundSql = ms.getBoundSql(parameterObject);
        return boundSql.getSql();
    }
    /**
     * 包装sql后，重置到invocation中
     * @param invocation
     * @param sql
     * @throws SQLException
     */
    public static void resetSql2Invocation(Invocation invocation, String sql) throws SQLException {
        final Object[] args = invocation.getArgs();
        MappedStatement statement = (MappedStatement) args[0];
        Object parameterObject = args[1];
        BoundSql boundSql = statement.getBoundSql(parameterObject);
        MappedStatement newStatement = newMappedStatement(statement, new BoundSqlSqlSource(boundSql));
        MetaObject msObject =  MetaObject.forObject(newStatement, new DefaultObjectFactory(), new DefaultObjectWrapperFactory(),new DefaultReflectorFactory());
        msObject.setValue("sqlSource.boundSql.sql", sql);
        args[0] = newStatement;
    }
    private static MappedStatement newMappedStatement(MappedStatement ms, SqlSource newSqlSource) {
        MappedStatement.Builder builder =
                new MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource, ms.getSqlCommandType());
        builder.resource(ms.getResource());
        builder.fetchSize(ms.getFetchSize());
        builder.statementType(ms.getStatementType());
        builder.keyGenerator(ms.getKeyGenerator());
        if (ms.getKeyProperties() != null && ms.getKeyProperties().length != 0) {
            StringBuilder keyProperties = new StringBuilder();
            for (String keyProperty : ms.getKeyProperties()) {
                keyProperties.append(keyProperty).append(",");
            }
            keyProperties.delete(keyProperties.length() - 1, keyProperties.length());
            builder.keyProperty(keyProperties.toString());
        }
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.resultSetType(ms.getResultSetType());
        builder.cache(ms.getCache());
        builder.flushCacheRequired(ms.isFlushCacheRequired());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }
    /**
     * 是否标记为区域字段
     * @return
     */
    public static boolean isAreaTag( MappedStatement mappedStatement) throws ClassNotFoundException {
        String id = mappedStatement.getId();
        //获取类名
        String className = id.substring(0, id.lastIndexOf("."));
        Class clazz = Class.forName(className);
        //获取方法名
        String methodName = id.substring(id.lastIndexOf(".") + 1);
        //这里是博主工作需求，防止pagehelper那里未生效
        if(methodName.contains("_COUNT")){
            methodName=methodName.replace("_COUNT","");
        }
        String m=methodName;
        Class classType = Class.forName(id.substring(0,mappedStatement.getId().lastIndexOf(".")));
        //获取对应拦截方法名
        String mName = mappedStatement.getId().substring(mappedStatement.getId().lastIndexOf(".") + 1);
        //这里是博主工作需求，防止pagehelper那里未生效
        if(mName.contains("_COUNT")){
            mName=mName.replace("_COUNT","");
        }
        boolean ignore = false;
        //获取该类(接口)的所有方法,如果你查询的方法就写在该类，就不需要下面的if判断
        Method[] declaredMethods = classType.getDeclaredMethods();
        Method declaredMethod = Arrays.stream(declaredMethods).filter(it -> it.getName().equals(m)).findFirst().orElse(null);
        //该判断是拿到该接口的超类的方法，博主的查询方法就在超类里，因此需要利用下面代码来获取对应方法
        if (declaredMethod == null) {
            Type[] genericInterfaces = clazz.getGenericInterfaces();
            declaredMethod = Arrays.stream(genericInterfaces).map(e ->
            {
                Method[] declaredMethods1 = ((Class) e).getDeclaredMethods();
                return Arrays.stream(declaredMethods1).filter(it -> it.getName().equals(m)).findFirst().orElse(null);
            }).filter(Objects::nonNull).findFirst().orElse(null);
        }
        if(declaredMethod!=null){
        //查询方法是否被permission标记注解
            ignore = declaredMethod.isAnnotationPresent(Permission.class);
        }
        return ignore;
    }
    /**
     * 是否标记为区域字段
     * @return
     */
    public static boolean isAreaTagIngore( MappedStatement mappedStatement) throws ClassNotFoundException {
        String id = mappedStatement.getId();
        String className = id.substring(0, id.lastIndexOf("."));
        Class clazz = Class.forName(className);
        String methodName = id.substring(id.lastIndexOf(".") + 1);
        Class classType = Class.forName(id.substring(0,mappedStatement.getId().lastIndexOf(".")));
        //获取对应拦截方法名
        String mName = mappedStatement.getId().substring(mappedStatement.getId().lastIndexOf(".") + 1);
        boolean ignore = false;
        Method[] declaredMethods = classType.getDeclaredMethods();
        Method declaredMethod = Arrays.stream(declaredMethods).filter(it -> it.getName().equals(methodName)).findFirst().orElse(null);
        if (declaredMethod == null) {
            Type[] genericInterfaces = clazz.getGenericInterfaces();
            declaredMethod = Arrays.stream(genericInterfaces).map(e ->
            {
                Method[] declaredMethods1 = ((Class) e).getDeclaredMethods();
                return Arrays.stream(declaredMethods1).filter(it -> it.getName().equals(methodName)).findFirst().orElse(null);
            }).filter(Objects::nonNull).findFirst().orElse(null);
        }
        ignore = declaredMethod.isAnnotationPresent(Permission.class);
        return ignore;
    }
    public static String getOperateType(Invocation invocation) {
        final Object[] args = invocation.getArgs();
        MappedStatement ms = (MappedStatement) args[0];
        SqlCommandType commondType = ms.getSqlCommandType();
        if (commondType.compareTo(SqlCommandType.SELECT) == 0) {
            return "select";
        }
        return null;
    }
    //    定义一个内部辅助类，作用是包装sq
    static class BoundSqlSqlSource implements SqlSource {
        private BoundSql boundSql;
        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }
        @Override
        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }
    }
}

步骤六

如果方法被permission注解进入if方法，查询各自数据权限，拼接sql，替换sql。如未进入则放行。

if (ExecutorPluginUtils.isAreaTag(mappedStatement)) {
            //获取该用户所具有的角色的数据权限dataScope
            //因数据敏感省略
            //获取该用户的所在公司或部门下的所有人
            //例如 StringBuffer orgBuffer = new StringBuffer();
            // orgBuffer.append("(");
            //String collect = allUserByOrgs.stream().map(String::valueOf).collect(Collectors.joining(","));
            //orgBuffer.append(collect).append(")");
            //String orgsUser = orgBuffer.toString();
            try {
                if (statement instanceof Select) {
                    Select selectStatement = (Select) statement;
                    //其中的PlainSelect 可以拿到sql语句的全部节点信息，具体各位可以看源码
                    PlainSelect plain = (PlainSelect) selectStatement.getSelectBody();
                    //获取所有外连接
                    List joins = plain.getJoins();
                    //获取到原始sql语句
                    String sql = processSql;
                    StringBuffer whereSql = new StringBuffer();
                    switch (dataScope) {
                    //这里dataScope  范围 1 所有数据权限  2 本人  3,部门及分部门(递归)  4.公司及分公司(递归)
                   //所有数据权限作用在人上，因此sql用 in 
                        case 1:
                            whereSql.append("1=1");
                            break;
                        case 2:
                            for (Join join : joins) {
                                Table rightItem = (Table) join.getRightItem();
                                //匹配表名
                                if(rightItem.getName().equals("sec_user")){
                                //获取别名
                                    if(rightItem.getAlias()!=null){
                                        whereSql.append(rightItem.getAlias().getName()).append(".id = ").append(SecurityUtils.getLoginUser().getId());
                                    }else {
                                        whereSql.append("id = ").append(deptsUser);
                                    }
                                }
                            }
                            break;
                        case 3:
                            for (Join join : joins) {
                                Table rightItem = (Table) join.getRightItem();
                                if(rightItem.getName().equals("sec_user")){
                                    if(rightItem.getAlias()!=null){
                                        whereSql.append(rightItem.getAlias().getName()).append(".id in ").append(deptsUser);
                                    }else {
                                        whereSql.append("id in ").append(deptsUser);
                                    }
                                }
                            }
                            break;
                        case 4:
                            for (Join join : joins) {
                                Table rightItem = (Table) join.getRightItem();
                                if(rightItem.getName().equals("sec_user")){
                                    if(rightItem.getAlias()!=null){
                                        whereSql.append(rightItem.getAlias().getName()).append(".id in ").append(orgsUser);
                                    }else {
                                        whereSql.append("id in ").append(deptsUser);
                                    }
                                }
                            }
                            break;
                    }
					//获取where节点
                    Expression where = plain.getWhere();
                    if (where == null) {
                        if (whereSql.length() > 0) {
                            Expression expression = CCJSqlParserUtil
                                    .parseCondExpression(whereSql.toString());
                            Expression whereExpression = (Expression) expression;
                            plain.setWhere(whereExpression);
                        }
                    } else {
                        if (whereSql.length() > 0) {
                            //where条件之前存在，需要重新进行拼接
                            whereSql.append(" and ( " + where.toString() + " )");
                        } else {
                            //新增片段不存在，使用之前的sql
                            whereSql.append(where.toString());
                        }
                        Expression expression = CCJSqlParserUtil
                                .parseCondExpression(whereSql.toString());
                        plain.setWhere(expression);
                    }
                    sql2Reset = selectStatement.toString();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        // 替换sql
        ExecutorPluginUtils.resetSql2Invocation(invocation, sql2Reset);
        //放行
        Object proceed = invocation.proceed();
        return proceed;