利用反射拼接sql語句

首先，創建一個Student類：

class Student{
    private int age;
    private String name;
    private Date date;

    public  Student(){}
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getDate() {
        return date;
    }
    public void setDate(Date date) {
        this.date = date;
    }
    public Student(int age, String name, Date date) {
        super();
        this.age = age;
        this.name = name;
        this.date = date;
    }


}

然後利用反射來拼接插入一個條數據

import java.lang.reflect.Field;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
public class ReflectDemo {
    public String insert(Object o){
        Class c = o.getClass();
        String tableName = c.getSimpleName();
        System.out.println(tableName);
        Field[] fields = c.getDeclaredFields();
        StringBuffer sb=new StringBuffer();
        for(Field f: fields){
            sb.append(f.getName() + ",");
        }
        String sql=sb.substring(0,sb.length()-1);
        String sql2="";
        StringBuffer sb2=new StringBuffer();
        try {
        Field[] fields2 = c.getDeclaredFields();
        for (Field f : fields2) {
            f.setAccessible(true);
                if(f.getType()==String.class){
                    sb2.append("'" + f.get(o) + "',");
                }else if(f.getType()==Date.class){
                    Date d=(Date) f.get(o);
                    DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
                    String str = df.format(d);
                    sb2.append("'" + str + "',");
                }else{
                    sb2.append(f.get(o) + ",");
                }
            }
        sql2=sb2.substring(0,sb2.length()-1);
        }catch (Exception e) {
                e.printStackTrace();
    }
        return "insert into " + tableName + "("
        + sql + ") values("
        + sql2 + ")";
    }

    public static void main(String[] args) {
        Student stu = new Student(1, "張三", new Date());
        ReflectDemo s = new ReflectDemo();
        String sql = s.insert(stu);
        System.out.println(sql);


    }
}

運行結果：
Student(age,name,date) values(1,’張三’,’2017-06-10’)