分析这段代码 List<Map> params = paperQuestion.getQuestionIdsList().stream().map(question -> { Map mp = new HashMap(); mp.put("paperId", paperQuestion.getPaperId()); mp.put("questionId", question.getId()); return mp; }).collect(Collectors.toList());

这段代码使用了Java 8中的Stream API，对List<PaperQuestion>对象中的questionIdsList属性进行了处理，将其转换为List<Map>类型的对象params。

具体的处理流程是：首先使用stream()方法将List<PaperQuestion>对象中的questionIdsList属性转换为Stream类型的对象，然后使用map()方法对其中的每一个元素进行映射操作。在这里，使用了Lambda表达式，将每一个Question对象转换为一个Map对象，其中Map的key为"paperId"，value为PaperQuestion对象的paperId属性的值；Map的key为"questionId"，value为Question对象的id属性的值。最后，使用collect()方法将所有Map对象收集起来，转换为List类型的对象。

总的来说，这段代码的作用是将List<PaperQuestion>对象中的questionIdsList属性中的每一个Question对象转换为一个包含paperId和questionId属性的Map对象，并将所有Map对象组成一个List返回。

相关问题

讲解一下这段代码List<String> list = map.getOrDefault(key, new ArrayList<String>());

这段代码的作用是从一个Map对象中获取与指定键关联的值，如果该键不存在，则返回一个新的ArrayList对象。具体解释如下：

1. map.getOrDefault(key, defaultValue)方法是Map接口中的一个方法，它的作用是获取与指定键关联的值。如果该键存在，则返回与该键关联的值；如果该键不存在，则返回defaultValue。

2. 在这段代码中，key是指定的键，map是要获取值的Map对象，而new ArrayList<String>()则是默认的值。如果指定的键不存在，则返回一个新的ArrayList对象。

3. 最后，将返回的值赋给一个List<String>类型的变量list，这个变量就是我们想要的与指定键关联的值。

总之，这段代码的作用是获取Map对象中指定键的值，并且如果该键不存在，则返回一个空的ArrayList对象。

List<DataPermissionSchemaEo> dataPermissionSchemaEoList = comDataComponent.getDataPermissionSchemaList(); List<SchemaRowRuleEo> schemaRowRuleList = comDataComponent.getSchemaRowRuleList(); List<SchemaColumnRuleEo> schemaColumnRuleList = comDataComponent.getSchemaColumnRuleList(); //设置行权限 根据用户id和用户组织去获取 List<SchemaRowRule> userRowRuleList = schemaRowRuleList.stream() .filter(schemaRowRuleEo -> { List<String> userList = JSONObject.parseArray(schemaRowRuleEo.getRowPermissionUserList(), String.class); List<String> orgList = JSONObject.parseArray(schemaRowRuleEo.getRowPermissionOrgList(), String.class); return userList.contains(userUid) || orgList.contains(orgCode) || userList.contains(WILDCARD) || orgList.contains(WILDCARD); }) .map(schemaRowRuleEo -> { SchemaRowRule schemaRowRule = new SchemaRowRule(); BeanUtils.copyProperties(schemaRowRuleEo, schemaRowRule); return schemaRowRule; }) .collect(Collectors.toList());List<SchemaColumnRule> userColumnRuleList = schemaColumnRuleList.stream() .filter(rule -> { List<String> userList = Optional.ofNullable(rule.getColumnPermissionUserList()) .map(userListStr -> JSONObject.parseArray(userListStr, String.class)) .orElse(Collections.emptyList()); List<String> orgList = Optional.ofNullable(rule.getColumnPermissionOrgList()) .map(orgListStr -> JSONObject.parseArray(orgListStr, String.class)) .orElse(Collections.emptyList()); return userList.contains(userUid) || orgList.contains(orgCode) || userList.contains(WILDCARD) || orgList.contains(WILDCARD); }) .map(rule -> { SchemaColumnRule columnRule = new SchemaColumnRule(); BeanUtils.copyProperties(rule, columnRule); return columnRule; }) .collect(Collectors.toList()); List<DataPermissionSchema> dataPermissionSchemaList = dataPermissionSchemaEoList.stream().map(dataPermissionSchemaEo -> { List<SchemaRowRule> schemaRowRules = userRowRuleList.stream() .filter(schemaRule -> dataPermissionSchemaEo.getDatabaseCode().equals(schemaRule.getDatabaseCode()) && dataPermissionSchemaEo.getSchemaCode().equals(schemaRule.getSchemaCode())) .collect(Collectors.toList()); List<SchemaColumnRule> schemaColumnRules = userColumnRuleList.stream() .filter(schemaRule -> dataPermissionSchemaEo.getDatabaseCode().equals(schemaRule.getDatabaseCode()) && dataPermissionSchemaEo.getSchemaCode().equals(schemaRule.getSchemaCode())) .collect(Collectors.toList()); if(!schemaRowRules.isEmpty() || !schemaColumnRules.isEmpty()) { DataPermissionSchema dataPermissionSchema = new DataPermissionSchema(); dataPermissionSchema.setDatabaseCode(dataPermissionSchemaEo.getDatabaseCode()); dataPermissionSchema.setSchemaCode(dataPermissionSchemaEo.getSchemaCode()); dataPermissionSchema.setSchemaRowRuleList(schemaRowRules); dataPermissionSchema.setSchemaColumnRuleList(schemaColumnRules); return dataPermissionSchema; } return null; }).filter(Objects::nonNull).collect(Collectors.toList());把这段代码改造成每个用户拥有的行权限和列权限

可以将该代码封装成一个方法，接收用户ID和组织代码作为参数，返回该用户拥有的行权限和列权限，代码如下：

public List<DataPermissionSchema> getUserDataPermissionSchema(String userUid, String orgCode) {
    List<DataPermissionSchemaEo> dataPermissionSchemaEoList = comDataComponent.getDataPermissionSchemaList();
    List<SchemaRowRuleEo> schemaRowRuleList = comDataComponent.getSchemaRowRuleList();
    List<SchemaColumnRuleEo> schemaColumnRuleList = comDataComponent.getSchemaColumnRuleList();

    // 获取用户行权限
    List<SchemaRowRule> userRowRuleList = schemaRowRuleList.stream()
            .filter(schemaRowRuleEo -> {
                List<String> userList = JSONObject.parseArray(schemaRowRuleEo.getRowPermissionUserList(), String.class);
                List<String> orgList = JSONObject.parseArray(schemaRowRuleEo.getRowPermissionOrgList(), String.class);
                return userList.contains(userUid) || orgList.contains(orgCode) || userList.contains(WILDCARD) || orgList.contains(WILDCARD);
            })
            .map(schemaRowRuleEo -> {
                SchemaRowRule schemaRowRule = new SchemaRowRule();
                BeanUtils.copyProperties(schemaRowRuleEo, schemaRowRule);
                return schemaRowRule;
            })
            .collect(Collectors.toList());

    // 获取用户列权限
    List<SchemaColumnRule> userColumnRuleList = schemaColumnRuleList.stream()
            .filter(rule -> {
                List<String> userList = Optional.ofNullable(rule.getColumnPermissionUserList())
                        .map(userListStr -> JSONObject.parseArray(userListStr, String.class))
                        .orElse(Collections.emptyList());
                List<String> orgList = Optional.ofNullable(rule.getColumnPermissionOrgList())
                        .map(orgListStr -> JSONObject.parseArray(orgListStr, String.class))
                        .orElse(Collections.emptyList());
                return userList.contains(userUid) || orgList.contains(orgCode) || userList.contains(WILDCARD) || orgList.contains(WILDCARD);
            })
            .map(rule -> {
                SchemaColumnRule columnRule = new SchemaColumnRule();
                BeanUtils.copyProperties(rule, columnRule);
                return columnRule;
            })
            .collect(Collectors.toList());

    // 获取用户权限所在的数据权限模板
    List<DataPermissionSchema> dataPermissionSchemaList = dataPermissionSchemaEoList.stream().map(dataPermissionSchemaEo -> {
        List<SchemaRowRule> schemaRowRules = userRowRuleList.stream()
                .filter(schemaRule -> dataPermissionSchemaEo.getDatabaseCode().equals(schemaRule.getDatabaseCode())
                        && dataPermissionSchemaEo.getSchemaCode().equals(schemaRule.getSchemaCode()))
                .collect(Collectors.toList());
        List<SchemaColumnRule> schemaColumnRules = userColumnRuleList.stream()
                .filter(schemaRule -> dataPermissionSchemaEo.getDatabaseCode().equals(schemaRule.getDatabaseCode())
                        && dataPermissionSchemaEo.getSchemaCode().equals(schemaRule.getSchemaCode()))
                .collect(Collectors.toList());
        if(!schemaRowRules.isEmpty() || !schemaColumnRules.isEmpty()) {
            DataPermissionSchema dataPermissionSchema = new DataPermissionSchema();
            dataPermissionSchema.setDatabaseCode(dataPermissionSchemaEo.getDatabaseCode());
            dataPermissionSchema.setSchemaCode(dataPermissionSchemaEo.getSchemaCode());
            dataPermissionSchema.setSchemaRowRuleList(schemaRowRules);
            dataPermissionSchema.setSchemaColumnRuleList(schemaColumnRules);
            return dataPermissionSchema;
        }
        return null;
    }).filter(Objects::nonNull).collect(Collectors.toList());

    return dataPermissionSchemaList;
}