概览

对于表中字段，需要实现多语言的方案探讨：

1.表中横向扩展多个字段分别存储中文，英文，俄语等语言字段，查询时，根据需要查询的语言，进行查询

2.增加一张多语言表，存储多语言信息，如图，同时基于mybatis-plus扩展插入更新查询等功能，完成代码无侵入的多语言功能

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一、组件的开发

1.自定义重写sql注入器ZlxSqlInjector

  @Override
    public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) {
        Class<?> modelClass = ReflectionKit.getSuperClassGenericType(mapperClass, Mapper.class, 0);
        if (modelClass != null) {
            String className = mapperClass.toString();
            Set<String> mapperRegistryCache = GlobalConfigUtils.getMapperRegistryCache(builderAssistant.getConfiguration());
            if (!mapperRegistryCache.contains(className)) {
                List<AbstractMethod> methodList = this.getMethodList(mapperClass);
                if (CollectionUtils.isNotEmpty(methodList)) {
                    ZlxTableInfo tableInfo = ZlxTableInfoHelper.initTableInfo(builderAssistant, modelClass,className);
                    // 循环注入自定义方法
                    methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));
                } else {
                    log.debug(mapperClass.toString() + ", No effective injection method was found.");
                }
                mapperRegistryCache.add(className);
            }
        }
    }
    @Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass) {
            return Stream.of(
                new com.zenglx.multilanguage.method.Insert(),
                new Delete(),
                new DeleteByMap(),
                new DeleteById(),
                new DeleteBatchByIds(),
                new Update(),
                new UpdateById(),
                new com.zenglx.multilanguage.method.SelectById(),
                new com.zenglx.multilanguage.method.SelectBatchByIds(),
                new SelectByMap(),
                new com.zenglx.multilanguage.method.SelectOne(),
                new com.zenglx.multilanguage.method.SelectCount(),
                new SelectMaps(),
                new SelectMapsPage(),
                new SelectObjs(),
                new com.zenglx.multilanguage.method.SelectList(),
                    new com.zenglx.multilanguage.method.SelectPage()
        ).collect(toList());
    }

2.自定义元数据和方法

@Getter
@Setter
public class ZlxTableInfo extends TableInfo {
    private String condition = SqlCondition.EQUAL;
    /**
     * 多语言字段
     */
    private Set<TableFieldInfo> multiLanguageColumns = new HashSet<>();

    /**
     * 实体类 => 主键信息
     */
    private Set<TableFieldInfo> entityClassPkColumns = new HashSet<>();

    /**
     * 实体类 => 全部列
     */
    private Set<TableFieldInfo> entityClassColumns = new HashSet<>();

    /**
     * 是否多语言
     */
    private boolean multiLanguage;

    public ZlxTableInfo(Class<?> entityType) {
        super(entityType);
    }


    public List<String> multiLanguageColumns() {
        return multiLanguageColumns.stream()
                .map(TableFieldInfo::getColumn).collect(Collectors.toList());
    }


    /**
     * 获取所有的查询的 sql 片段
     *
     * @param ignoreLogicDelFiled 是否过滤掉逻辑删除字段
     * @param withId              是否包含 id 项
     * @param prefix              前缀
     * @return sql 脚本片段
     */
    @Override
    public String getAllSqlWhere(boolean ignoreLogicDelFiled, boolean withId, final String prefix) {
        final String newPrefix = prefix == null ? EMPTY : prefix;
        String filedSqlScript = super.getFieldList().stream()
                .filter(i -> {
                    if (ignoreLogicDelFiled) {
                        return !(isWithLogicDelete() && i.isLogicDelete());
                    }
                    return true;
                })
                .map(i -> getSqlWhere(newPrefix,i)).filter(Objects::nonNull).collect(joining(NEWLINE));
        if (!withId || StringUtils.isBlank(super.getKeyProperty())) {
            return filedSqlScript;
        }
        String newKeyProperty = newPrefix + super.getKeyProperty();
        String keySqlScript = super.getKeyColumn() + EQUALS + SqlScriptUtils.safeParam(newKeyProperty);
        return SqlScriptUtils.convertIf(keySqlScript, String.format("%s != null", newKeyProperty), false)
                + NEWLINE + filedSqlScript;
    }

    private String convertIfProperty(String prefix, String property) {
        return StringUtils.isNotBlank(prefix) ? prefix.substring(0, prefix.length() - 1) + "['" + property + "']" : property;
    }

    /**
     * 获取 查询的 sql 片段
     *
     * @param prefix 前缀
     * @return sql 脚本片段
     */
    public String getSqlWhere(final String prefix,TableFieldInfo tableFieldInfo) {
        final String newPrefix = prefix == null ? EMPTY : prefix;
        // 默认:  AND column=#{prefix + el}
        String sqlScript = " AND " + String.format(condition, tableFieldInfo.getColumn(), newPrefix + tableFieldInfo.getEl());
        if(this.getMultiLanguageColumns().contains(tableFieldInfo)) {
            sqlScript = " AND " + String.format(condition, "t."+tableFieldInfo.getColumn(), newPrefix + tableFieldInfo.getEl());
        }
        // 查询的时候只判非空
        return convertIf(sqlScript, convertIfProperty(newPrefix, convertIfProperty(newPrefix, tableFieldInfo.getProperty())), tableFieldInfo);
    }

    /**
     * 转换成 if 标签的脚本片段
     *
     * @param sqlScript     sql 脚本片段
     * @param property      字段名
     * @param tableFieldInfo 验证策略
     * @return if 脚本片段
     */
    private String convertIf(final String sqlScript, final String property, TableFieldInfo tableFieldInfo) {
        if (tableFieldInfo.getWhereStrategy() == FieldStrategy.NEVER) {
            return null;
        }
        if (tableFieldInfo.isPrimitive() || tableFieldInfo.getWhereStrategy() == FieldStrategy.IGNORED) {
            return sqlScript;
        }
        if (tableFieldInfo.getWhereStrategy() == FieldStrategy.NOT_EMPTY && tableFieldInfo.isCharSequence()) {
            return SqlScriptUtils.convertIf(sqlScript, String.format("%s != null and %s != ''", property, property),
                    false);
        }
        return SqlScriptUtils.convertIf(sqlScript, String.format("%s != null", property), false);
    }

}

public class SelectById extends com.baomidou.mybatisplus.core.injector.methods.SelectById {

    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        ZlxTableInfo zlxTableInfo = (ZlxTableInfo)tableInfo;
        if(zlxTableInfo.isMultiLanguage()) {
            SqlMethod sqlMethod = SqlMethod.SELECT_BY_ID;
            String scriptSql = "<script>SELECT %s FROM %s WHERE %s \n</script>";
            String sql = String.format(scriptSql, SqlHelper.getAllColumns(tableInfo), SqlHelper.selectFromTableTl(tableInfo),
                    sqlWhereEntityWrapper(true, tableInfo));
            SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
            return this.addSelectMappedStatementForTable(mapperClass, getMethod(sqlMethod), sqlSource, tableInfo);
        } else {
           return super.injectMappedStatement(mapperClass, modelClass, tableInfo);
        }
    }

    @Override
    protected String sqlWhereEntityWrapper(boolean newLine, TableInfo tableInfo) {
        ZlxTableInfo zlxTableInfo = (ZlxTableInfo)tableInfo;
        if(zlxTableInfo.isMultiLanguage()) {
            StringBuilder sb = new StringBuilder();
            sb.append("b.").append(zlxTableInfo.getKeyColumn())
                    .append("=#{id}");
            return sb.toString();
        } else {
            return super.sqlWhereEntityWrapper(newLine, tableInfo);
        }

    }
}

3.自定义拦截器

 public class ZlxMultiLanguageInterceptor extends PaginationInnerInterceptor {


@Override
    public void beforeUpdate(Executor executor, MappedStatement statement, Object parameter) throws SQLException {
        ZlxTableInfo tableInfo = ZlxTableInfoHelper.getTableByMapper(getMapperClassName(statement.getId()));
        if (tableInfo != null && tableInfo.isMultiLanguage()) {
            Connection connection = executor.getTransaction().getConnection();
            switch (statement.getSqlCommandType()) {
                case INSERT:
                    insertMultiLanguage(tableInfo, parameter, connection);
                    break;
                case UPDATE:
                    List<String> columnNameList = tableInfo.getEntityClassColumns().stream().map(TableFieldInfo::getColumn)
                                    .collect(Collectors.toList());
                    updateMultiLanguage(tableInfo, parameter, connection, new HashSet<>(columnNameList));
                    break;
                case DELETE:
                    proceedDeleteMultiLanguage(tableInfo, parameter, connection);
                    break;
                default:
                    break;
            }
        }
    }

}

二、组件的使用

1.新建表

原表t_user，多语言表t_user_tl

2.引入库

<dependency>
    <groupId>com.zenglx.multilanguage</groupId>
    <artifactId>multilanguage-spring-boot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

3.demo验证测试

 

@RequestMapping("/v1/demo")
public class DemoController {

    @Autowired
    private UserService userService;

    /**
     * 新增用户
     *
     * @return
     */
    @PostMapping
    public ResponseEntity add(@RequestBody User user) {
        userService.save(user);
        return ResponseEntity.ok("成功");
    }

    /**
     * 用户详情
     *
     * @return
     */
    @GetMapping
    public ResponseEntity<User> get(@RequestParam("id") Long id) {
        return ResponseEntity.ok(userService.getById(id));
    }

    /**
     * 查询用户列表
     *
     * @return
     */
    @GetMapping("/list")
    public ResponseEntity<List<User>> list() {
        return ResponseEntity.ok(userService.list());
    }

    /**
     * 更新用户
     *
     * @return
     */
    @PutMapping
    public ResponseEntity update(@RequestBody User user) {
        userService.update(user,null);
        return ResponseEntity.ok("成功");
    }


    /**
     * 删除用户
     *
     * @return
     */
    @DeleteMapping
    public ResponseEntity delete(@RequestParam("id") Long id) {
        userService.removeById(id);
        return ResponseEntity.ok("成功");
    }


    @GetMapping("/page")
    public ResponseEntity<Page<User>> page(@RequestParam(required = false, value = "name") String name,
                                                         @RequestParam(defaultValue = "1", value = "page") Integer page,
                                                         @RequestParam(defaultValue = "10", value = "pageSize") Integer pageSize) {
        Page<User> param = new Page<>(page,pageSize);
        LambdaQueryWrapper<User> lambdaQueryWrapper = new LambdaQueryWrapper<>();
        lambdaQueryWrapper.like(StringUtils.hasText(name),User::getName,name);
        Page<User> userPage = userService.page(param,lambdaQueryWrapper);
        return ResponseEntity.ok(userPage);
    }

   a.用户添加

b.用户查询

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总结

可运行源码