Java整合mybatis實現(xiàn)過濾數(shù)據(jù)

更新時間：2023年01月14日 10:11:33 作者：我有一只肥螳螂

這篇文章主要介紹了Java整合mybatis實現(xiàn)過濾數(shù)據(jù)，文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值，需要的朋友們下面隨著小編來一起學習吧

場景

權限1：只能看到自己創(chuàng)建的數(shù)據(jù)
權限2：只能看到本部門的數(shù)據(jù)
權限3：查看全部數(shù)據(jù)

例子

小明有權限1：

{
    "code": "200",
    "msg": "查詢成功",
    "data": [
        {
            "name": "name1",
            "id": "1",
            "creater": "xiaoming"
        },
        {
            "name": "name2",
            "id": "2",
            "creater": "xiaoming"
        }
    ]
}

大明具有權限2，小明相同部門

{
    "code": "200",
    "msg": "查詢成功",
    "data": [
        {
            "name": "name1",
            "id": "1",
            "creater": "xiaoming"
        },
        {
            "name": "name2",
            "id": "2",
            "creater": "xiaoming"
        },
        {
            "name": "name3",
            "id": "3",
            "creater": "daming"
        },
        {
            "name": "name4",
            "id": "4",
            "creater": "daming"
        }
    ]
}

領導有權限3，可以看到全部

{
    "code": "200",
    "msg": "查詢成功",
    "data": [
        {
            "name": "name1",
            "id": "1",
            "creater": "xiaoming"
        },
        {
            "name": "name2",
            "id": "2",
            "creater": "xiaoming"
        },
        {
            "name": "name3",
            "id": "3",
            "creater": "daming"
        },
        {
            "name": "name4",
            "id": "4",
            "creater": "daming"
        },
        {
            "name": "name5",
            "id": "5",
            "creater": "mingming"
        }
    ]
}

執(zhí)行流程

Configuration：初始化基礎配置，比如 MyBatis 的別名等，一些重要的類型對象，如插件，映射器，ObjectFactory 和 TypeHandler對象， MyBatis所有的配置信息都維持在 Configuration 對象之中。
SqlSessionFactory：SqlSession工廠。
SqlSession：作為MyBatis工作的主要頂層API，表示和數(shù)據(jù)庫交互的會話，完成必要的數(shù)據(jù)庫增刪改查功能。
Executor：真正執(zhí)行sql語句的對象，調用 sqlSession 的方法時，本質上都是調用 executor 的方法，還負責獲取 connection，創(chuàng)建 StatementHandler ，責調用 StatementHandler 操作數(shù)據(jù)庫，并把結果集通過 ResultSetHandler 進行自動映射，另外，它還處理二級緩存的操作。
StatementHandler：可以理解為是一次語句的執(zhí)行，創(chuàng)建并持有 ParameterHandler 和 ResultSetHandler 對象，操作 dbc 的statement與進行數(shù)據(jù)庫操作，另外它也實現(xiàn)了MyBatis的一級緩存。
ParameterHandler：處理入?yún)ⅲ瑢ava方法上的參數(shù)設置到被執(zhí)行語句中
ResultSetHandler：處理返回結果，處理jdbc的返回值，將其轉換為java的對象
TypeHandler：負責Java數(shù)據(jù)類型和JDBC數(shù)據(jù)類型之間的映射和轉換，在 ParameterHandler 和 ResultsetHandler 中
MappedStatement：MappedStatement維護了一條 <select|update|delete|insert> 節(jié)點的封裝。
SqlSource：負責根據(jù)用戶傳遞的 parameterObject，動態(tài)地生成 SQL 語句，將信息封裝到 BoundSql 對象中，并返回。
BoundSql：表示動態(tài)生成的 SQL 語句以及相應的參數(shù)信息。

配置切面

Interceptor：實現(xiàn) Interceptor 接口，mybatis 的攔截器
@Intercepts：只有一個屬性，即value，其返回值類型是一個@Signature類型的數(shù)組，表示我們可以配置多個@Signature注解
@Signature：一個方法簽名，其共有三個屬性，分別為：type、method、args
type：攔截的四種類型：Executor - 執(zhí)行器方法、StatementHandler - 攔截SQL語法構建處理、ParameterHandler - 攔截參數(shù)處理、ResultSetHandler - 攔截結果集處理
method：對應接口中的某一個方法名，比如 Executor 的 query 方法
args：對應接口中的某一個方法的參數(shù)，比如 Executor 中 query 方法因為重載原因，有多個，args就是指明參數(shù)類型，從而確定是具體哪一個方法；

@Intercepts({<!--{cke_protected}{C}%3C!%2D%2D%20%2D%2D%3E-->@Signature(type = org.apache.ibatis.executor.Executor.class, method = "query", args = {<!--{cke_protected}{C}%3C!%2D%2D%20%2D%2D%3E-->MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})@Slf4jpublic class MapperPermissionInterceptor implements Interceptor {<!--{cke_protected}{C}%3C!%2D%2D%20%2D%2D%3E--> @Override public Object intercept(Invocation invocation) throws Throwable {<!--{cke_protected}{C}%3C!%2D%2D%20%2D%2D%3E--> Object target = invocation.getTarget(); //被代理對象 Method method = invocation.getMethod(); //代理方法 Object[] args = invocation.getArgs(); //方法參數(shù)MappedStatement mappedStatement = (MappedStatement) args[0]; Object parameterObject = args[1]; // do something ...方法攔截前執(zhí)行代碼塊 Object result = invocation.proceed(); // do something ...方法攔截后執(zhí)行代碼塊 return result; } }@Intercepts({@Signature(type = org.apache.ibatis.executor.Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
@Slf4j
public class MapperPermissionInterceptor implements Interceptor {
 @Override
    public Object intercept(Invocation invocation) throws Throwable {
		Object target = invocation.getTarget(); //被代理對象
        Method method = invocation.getMethod(); //代理方法
        Object[] args = invocation.getArgs(); //方法參數(shù)
		MappedStatement mappedStatement = (MappedStatement) args[0];
        Object parameterObject = args[1];
        // do something ...方法攔截前執(zhí)行代碼塊
        Object result = invocation.proceed();
        // do something ...方法攔截后執(zhí)行代碼塊
        return result;
    }
  }

方案

原 originalSql

select id, name, creater from tt

通過 mybatis 的切面實現(xiàn)

在前面添加 select * from ( ，后面添加 where 條件

select * from ( 
	select id, name, creater from tt
) tmp 
where creater = "daming"

實現(xiàn)

配置權限開關
判斷方法名是否包含 list 或者 page
添加 where 條件

@Intercepts({@Signature(type = org.apache.ibatis.executor.Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
@Slf4j
public class MapperPermissionInterceptor implements Interceptor {
    @Autowired
    PermissionProperty permissionProperty;
    public static final String PACK_START_SQL = "select * from ( ";
    public static final String PACK_END_SQL = ") tmp ";
    public static final String PERMISSION_Y = "y";
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        if(!PERMISSION_Y.toLowerCase().equals(permissionProperty.getMapper().toLowerCase())){
            log.info("mapper 權限未開啟");
            return invocation.proceed();
        }
        MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
        Object parameter = invocation.getArgs()[1];
        BoundSql boundSql = mappedStatement.getBoundSql(parameter);
        String originalSql = boundSql.getSql().trim();
        String id = mappedStatement.getId();
        log.info("originalSql: {} ", originalSql);
        log.info("id: {}", id);
        String name = getMapperName(id);
        String method = getMapperMethod(id);
        log.info("name: {}, method: {}  ", name, method);
        String joinSql = dataPermissionSqlProvider().getJoinSql(name, method);
        log.info("joinSql: {} ", joinSql);
        if (Optional.ofNullable(joinSql).isPresent()) {
            BoundSql newBoundSql = copyFromBoundSql(mappedStatement, boundSql, this.joinSql(originalSql, joinSql));
            ParameterMap map = mappedStatement.getParameterMap();
            MappedStatement newMs = copyFromMappedStatement(mappedStatement, new BoundSqlSqlSource(newBoundSql), map);
            invocation.getArgs()[0] = newMs;
        }
        return invocation.proceed();
    }
    /**
     * 獲取 Mapper 名稱
     * @param id
     * @return
     */
    private String getMapperName(String id) {
        String name = id.substring(0, id.lastIndexOf("."));
        return name.substring(name.lastIndexOf(".") + 1);
    }
    /**
     * 獲取 Mapper 方法
     * @param id
     * @return
     */
    private String getMapperMethod(String id) {
        String method = id.substring(id.lastIndexOf(".") + 1);
        return method;
    }
    private DataPermissionProvider dataPermissionSqlProvider() {
        return (DataPermissionProvider) ApplicationContextUtil.getBean("dataPermissionProvider");
    }
    private String joinSql(String sql, String selectSql) {
        sql = PACK_START_SQL + sql + PACK_END_SQL + selectSql;
        log.info("packSql: {}", sql);
        return sql;
    }
    public static class BoundSqlSqlSource implements SqlSource {
        BoundSql boundSql;
        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }
        @Override
        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }
    }
    private BoundSql copyFromBoundSql(MappedStatement ms, BoundSql boundSql, String sql) {
        BoundSql newBoundSql = new BoundSql(ms.getConfiguration(), sql, boundSql.getParameterMappings(), boundSql.getParameterObject());
        for (ParameterMapping mapping : boundSql.getParameterMappings()) {
            String prop = mapping.getProperty();
            if (boundSql.hasAdditionalParameter(prop)) {
                newBoundSql.setAdditionalParameter(prop, boundSql.getAdditionalParameter(prop));
            }
        }
        return newBoundSql;
    }
    /**
     * 復制MappedStatement對象
     */
    private MappedStatement copyFromMappedStatement(MappedStatement ms, SqlSource newSqlSource, ParameterMap parameterMap) {
        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());
        builder.timeout(ms.getTimeout());
        builder.parameterMap(parameterMap);
        builder.resultMaps(ms.getResultMaps());
        builder.resultSetType(ms.getResultSetType());
        builder.cache(ms.getCache());
        builder.flushCacheRequired(ms.isFlushCacheRequired());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }
}

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