resultMap生成

public class Generator {
    private static final String FORMAT_ERROR = "数据格式错误";

    /**
     * resultMap拼接词缀
     */
    private static final String QUOTATION_MARK = "\"";
    private static final String RESULT_PREFIX = "<result property=";
    private static final String RESULT_COLUMN = " column=";
    private static final String RESULT_JDBCTYPE = " jdbcType=";
    private static final String RESULT_SUFFIX = "/>";

    /**
     * jdbc类型映射，java类型 - mybatis类型
     */
    private static Map<String, String> jdbcTypeMap;


    /**
     * 生成resultMap下单行result
     *
     * @param formatData 格式化数据，格式为 private type field;   只解析field，根据type转换
     * @return 格式化结果，格式为 <result property="java_field" column="database_field" jdbcType="JType"></result>
     * column为数据库字段，大写字母转换成_ ， jdbcType按照MyBatis内置格式转换
     */
    public static String singleResultMapGenerator(String formatData) {
        if (formatData == null || formatData.length() == 0) return formatData;
        //按照空格格式化
        String[] splits = formatData.split(" ");
        if (splits.length < 2) return FORMAT_ERROR;
        //初始化map
        initJdbcTypeMap();
        StringBuilder result = new StringBuilder(RESULT_PREFIX);
        //只取最后两个数据，注意符号;
        splits[splits.length - 1] = splits[splits.length - 1].substring(0, splits[splits.length - 1].length() - 1);
        result.append(QUOTATION_MARK).append(splits[splits.length - 1]).append(QUOTATION_MARK)
                .append(RESULT_COLUMN).append(QUOTATION_MARK).append(humpConvertUnderline(splits[splits.length - 1])).append(QUOTATION_MARK);
        if (!jdbcTypeMap.containsKey(splits[splits.length - 2])) {
            return FORMAT_ERROR;
        }
        result.append(RESULT_JDBCTYPE).append(QUOTATION_MARK).append(jdbcTypeMap.get(splits[splits.length - 2])).append(QUOTATION_MARK)
                .append(RESULT_SUFFIX);

        return result.toString();
    }

    /**
     * 多行resultMap生成result
     *
     * @param formatData 格式化数据，有标准换行
     * @return 有标准换行的result标签
     */
    public static String multiResultMapGenerator(String formatData) {
        if (formatData == null || formatData.length() == 0) return formatData;
        String[] splits = formatData.split("\n");
        StringBuilder result = new StringBuilder();
        for (String s : splits) {
            result.append(singleResultMapGenerator(s)).append("\n");
        }
        return result.toString();
    }

    public static void main(String[] args) {
        System.out.println(multiResultMapGenerator("  private Integer id;\n" +
                "  private String applyId;\n" +
                "  private java.sql.Timestamp applyDate;"));
    }

    /**
     * 将驼峰命名转换为下划线命名
     */
    private static String humpConvertUnderline(String humpData) {
        if (humpData == null || humpData.length() <= 1) return humpData;
        StringBuilder result = new StringBuilder();
        //寻找变换位置
        for (int var1 = 0; var1 < humpData.length(); var1++) {
            if ('A' <= humpData.charAt(var1) && humpData.charAt(var1) <= 'Z') {
                result.append("_").append((char) (humpData.charAt(var1) + 32));
            } else {
                result.append(humpData.charAt(var1));
            }
        }
        return result.toString();
    }

    /**
     * 映射初始化，需要时使用
     * 初始化，保证原子性
     */
    private synchronized static void initJdbcTypeMap() {
        if (jdbcTypeMap == null) {
            jdbcTypeMap = new HashMap<>();
            jdbcTypeMap.put("String", "VARCHAR");
            jdbcTypeMap.put("BegDecimal", "DECIMAL");
            jdbcTypeMap.put("boolean", "BOOLEAN");
            jdbcTypeMap.put("Boolean", "BOOLEAN");
            jdbcTypeMap.put("byte", "TINYINT");
            jdbcTypeMap.put("Byte", "TINYINT");
            jdbcTypeMap.put("short", "SMALLINT");
            jdbcTypeMap.put("Short", "SMALLINT");
            jdbcTypeMap.put("int", "INTEGER");
            jdbcTypeMap.put("Integer", "INTEGER");
            jdbcTypeMap.put("long", "LONG");
            jdbcTypeMap.put("Long", "LONG");
            jdbcTypeMap.put("float", "REAL");
            jdbcTypeMap.put("Float", "REAL");
            jdbcTypeMap.put("double", "DOUBLE");
            jdbcTypeMap.put("Double", "DOUBLE");
            jdbcTypeMap.put("byte[]", "BINARY");
            jdbcTypeMap.put("Date", "DATE");
            jdbcTypeMap.put("Time", "TIME");
            jdbcTypeMap.put("Timestamp", "TIMESTAMP");
            jdbcTypeMap.put("java.sql.Timestamp", "TIMESTAMP");
            jdbcTypeMap.put("Clob", "CLOB");
            jdbcTypeMap.put("Blob", "BLOB");
            jdbcTypeMap.put("Array", "ARRAY");
            jdbcTypeMap.put("Struct", "STRUCT");
            jdbcTypeMap.put("Ref", "REF");
            jdbcTypeMap.put("URL", "DATALINK");
        }
    }

}