JAVA注解model拼接sql语句创建表

package com.wind.test.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**

---

• 文件名称 : DataBaseTable.java
• 作 者 : Ranger
• 创建时间 : 2015-1-12 上午9:27:49
• 文件描述 :注解得到表名
• 修改历史 : 2015-1-12 1.00 初始版本

---

*/
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface DataBaseTable {
public String tableName();
}

package com.wind.test.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**

---

• 文件名称 : ColumnsName.java
• 作 者 : Ranger
• 创建时间 : 2015-1-12 上午9:25:30
• 文件描述 : 注解字段，得到字段名
• 修改历史 : 2015-1-12 1.00 初始版本

---

*/
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ColumnsName {
String fieldName() default "";
}

package com.wind.test.annotationTest.model;

import com.wind.test.annotation.ColumnsName;
import com.wind.test.annotation.DataBaseTable;

@DataBaseTable(tableName = "CustomModel")
public class CustomModel{

@ColumnsName(fieldName = "userId")
public String a_mImUserId;

@ColumnsName(fieldName = "UserCustomList")
public byte[] b_mUserCustomList;

@ColumnsName(fieldName = "datatype")
public int c_mType;

}

package com.wind.test.annotationTest;

import java.lang.reflect.Field;
import java.lang.reflect.Type;

import com.wind.test.annotation.ColumnsName;
import com.wind.test.annotation.DataBaseTable;
import com.wind.test.annotationTest.model.CustomModel;

public class AnnotationTest {

/**
 * 运行注解，拼出sql
 * @param args
 * @throws Exception
 */
public static void main(String[] args) throws Exception {
    Field[] fields = CustomModel.class.getFields();
    DataBaseTable tableModel = (DataBaseTable) CustomModel.class.getAnnotation(DataBaseTable.class);
    String tableName = tableModel.tableName();
    String sql = "CREATE TABLE IF NOT EXISTS "  + tableName + "(";
    for (int i = 0; i < fields.length; i++) {
         ColumnsName tabFeild = fields[i].getAnnotation(ColumnsName.class);
        if(tabFeild != null){
            if(i == 0){
                sql = sql + tabFeild.fieldName() + " " + getColumnType(fields[i].getType());
            }else{
                sql =sql + " ," + tabFeild.fieldName() + " " + getColumnType(fields[i].getType());
            }
        }
    }
    sql = sql + ");";
    System.out.println(sql);
}

/**
 * 得到type
 * @param type
 * @return
 */
public static String getColumnType(Type type) {
    String colums = "TEXT";
    if (type == Long.class || (type == Long.TYPE)) {

    } else if (Integer.class == type || (type == Integer.TYPE)) {
        colums = "INTEGER";
    } else if (type == String.class) {

    } else if (type == byte[].class) {
        colums = "BLOB";
    }

    return colums;
}

}