如果一個實體類欄位特別多，那麼建立對應的RDBMS對應的表會讓我感到抓狂，可以利用Java反射特性，生產對應欄位
1.建立一個藉口，定義一些常量

public interface Constants {

    /**引數預設值*/
    public static final String DEFAULT_PARAM_VAL = "";
    /**中文字符集*/
    public static final String CHAR_UTF8 = "utf-8";
    /**資料預設分隔符*/
    public static final String DEFAULT_SEPAREATOR = "|"
 
;
    /**欄位預設分隔符*/
    public static final String DEFAULT_FIELDS_SEPAREATOR = ",";
    /**空格字串*/
    public static final String BLANK_SPACE = " ";
    /**換行字元*/
    public static final String LINE_FEED = "\n";
    /**製表符字元*/
    public static final String TAB = "\t";

}

2.建立一個列舉類，定義一些常用語句 （可以根據，你自己的需求定義）

/**
 * 
 * @author puppy
 * @data 2015-04-02
 *
 */
 

public enum HiveTableSyntax {

    external("CREATE EXTERNAL TABLE ","external"),inner("CREATE TABLE ","inner"),
    defalut("PARTITIONED BY(logdate String) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' ","default"),
    sequence("PARTITIONED BY(logdate String) ROW FORMAT DELIMITED FIELDS TERMINATED BY '|' STORED AS SequenceFile "
 
,"sequence");

    private String value;
    private String index;

    private HiveTableSyntax() {
    }
    private HiveTableSyntax(String value) {
        this.value=value;
    }
    private HiveTableSyntax(String value,String index)  
    {  
        this.value=value;
        this.index=index;
    }  
    public static String getValue(String index){
        for(HiveTableSyntax hts:HiveTableSyntax.values()){
            if(hts.getIndex().equalsIgnoreCase(index)){
                return hts.getValue();
            }
        }
        return null;
    }
    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public String getIndex() {
        return index;
    }

    public void setIndex(String index) {
        this.index = index;
    }


}

3.建立生成表的類 （我這裡只寫了生成hive表，對應其他 請自己定義）

/**
 * 
 * @author puppy
 * @date 2015-04-01
 *
 */
public class AutoCreateFields {
    // 生成欄位
    public static String create(Class<?> clazz) {

        Field[] fs = clazz.getDeclaredFields();
        Class<?> superClazz = clazz.getSuperclass();
        if (superClazz != null) {
            Field[] superFs = superClazz.getDeclaredFields();
            fs = (Field[]) ArrayUtils.addAll(fs, superFs);
        }
        StringBuffer sb = new StringBuffer();
        sb.append(Constants.LINE_FEED);
        sb.append("(");
        int size = fs.length;
        for (int i = 0; i < size; i++) {

            Field field = fs[i];
            field.setAccessible(true);
            sb.append(field.getName());
            sb.append(Constants.BLANK_SPACE);
            sb.append(field.getType().getSimpleName().equalsIgnoreCase("Integer")?"int":field.getType().getSimpleName());
            if (i + 1 != size) {

                sb.append(Constants.DEFAULT_FIELDS_SEPAREATOR);
                sb.append(Constants.LINE_FEED);
            }
        }
        sb.append(")");
        sb.append(Constants.LINE_FEED);
        return sb.toString();
    }
    //生成hive表
    public static String createHiveTable(Class<?> clazz,String tblname,String externalOrInner,String storeTpye){
        StringBuilder sb=new StringBuilder();
        String fields=create(clazz);
        String create=HiveTableSyntax.getValue(externalOrInner);
        String st=HiveTableSyntax.getValue(storeTpye);
        sb.append(create);
        sb.append(tblname);
        sb.append(fields);
        sb.append(st);
        return sb.toString();
    }
    public static void main(String[] args) {
        String result="Need Params:aqy or partner or v1 or default";

        if(args.length>0&&StringUtils.isNotBlank(args[0])){
            String value=args[0];

            switch (value){
            case "aqy":
                result=createHiveTable(AQYLogOriginal.class,"qiyi_log_original","external","sequence");
                break;
            case "partner":
                result=createHiveTable(PartnerLogOriginal.class,"partner_log_original","external","sequence");
                break;
            case "v1":
                result=createHiveTable(V1VodLogOriginal.class,"v1_log_original","external","sequence");
                break;
                default:
                result=createHiveTable(V1VodLogOriginal.class,"v0v1_log_original","external","sequence");   
                break;
            }

        }
        //String aqy = createHiveTable(AQYLogOriginal.class,"qiyi_log_original","external","sequence");
        //String partner = createHiveTable(PartnerLogOriginal.class,"partner_log_original","external","sequence");
        //String v1 = createHiveTable(V1VodLogOriginal.class,"v0v1_log_original","inner","sequence");
        System.out.println(result);
    }