java反射技术与类使用示例
package com.java.db;
import java.lang.reflect.constructor;
import java.lang.reflect.field;
import java.lang.reflect.invocationtargetexception;
import java.lang.reflect.method;
import java.util.arraylist;
import java.util.arrays;
import java.util.iterator;
import java.util.list;
import java.util.map;
import com.java.entity.bookshelf;
import com.java.util.getmetadatacloumname;
public class getnewinstances<t> {
class[] cl = {};
object[] ob = {};
/**
* 每次用完之后设为空 不然会累加
*/
public void setnulltoarrays(){
this.cl = new class[]{};
this.ob = new object[]{};
}
/**
* copy object数组
*
* @param obj
* 构造方法里需要的实际值
* @return
*/
public object[] getobjectarrays(object obj) {
ob = arrays.copyof(ob,ob.length + 1);
ob[ob.length - 1] = obj;
return ob;
}
/**
* copy class 数组
*
* @param cla
* 要添加的class
*
* @return
*/
@suppresswarnings("unchecked")
public class[] getclassarrays(class<?> cla) {
if (cla != null) {
cl = arrays.copyof(cl,cl.length + 1);
cl[cl.length - 1] = cla;
return cl;
}else{
return cl;
}
}
/**
* 得到类的实例
*
* @param clazz
* 要实例化的类
* @return 实例化之后的类
* @throws instantiationexception
* @throws illegalaccessexception
* @throws illegalargumentexception
* @throws securityexception
* @throws invocationtargetexception
* @throws nosuchmethodexception
*/
@suppresswarnings("unchecked")
public object getclassnewinstance(class<?> clazz)
throws instantiationexception, illegalaccessexception,
illegalargumentexception, securityexception,
invocationtargetexception, nosuchmethodexception {
object oj = null;
constructor[] cons = clazz.getdeclaredconstructors();// 得到构造函数
class[] cla = cons[1].getparametertypes();
system.out.println("提示用户是否需要添加字段 构造函数参数的大小:"+cla.length);
for (int i = 0; i < cla.length; i++) {
string classstr = cla[i].tostring();
// system.out.println("参数的类型："+classstr);
if (classstr.equals("class java.lang.string")) {
getclassarrays(string.class);
} else if (classstr.equals("int")) {
getclassarrays(int.class);
} else if (classstr.equals("double")) {
getclassarrays(double.class);
} else if (classstr.equals("boolean")) {
getclassarrays(boolean.class);
} else if (classstr.equals("float")) {
getclassarrays(float.class);
} else if (classstr.equals("class java.lang.integer")) {
getclassarrays(integer.class);
}else if(classstr.equals("class java.lang.float")){
getclassarrays(float.class);
}
}
oj = clazz.newinstance();//返回当前对象 具体的实例化构造在bdoperater
return oj;
}
/**
* 通过构造函数得到具体的实例类
* @param clazz
* @return
* @throws illegalargumentexception
* @throws securityexception
* @throws instantiationexception
* @throws illegalaccessexception
* @throws invocationtargetexception
* @throws nosuchmethodexception
*/
public object getobjcon(class<?> clazz) throws illegalargumentexception, securityexception, instantiationexception, illegalaccessexception, invocationtargetexception, nosuchmethodexception{
object obj=null;
obj = this.getclassnewinstance(clazz);
return obj;
}
/**
* 得到对象的实例
* @param clazz
* @return
* @throws instantiationexception
* @throws illegalaccessexception
*/
public object getnewinstance(class clazz) throws instantiationexception, illegalaccessexception{
object obj = null;
obj = clazz.newinstance();
return obj;
}
/**
* 根据反射得到类中的所有属性
* @param clazz 需要被获取属性的类
* @return 属性集合
* @throws securityexception
* @throws illegalargumentexception
* @throws instantiationexception
* @throws illegalaccessexception
* @throws invocationtargetexception
* @throws nosuchmethodexception
*/
public field[] getfielsdarray(class<object> clazz) throws securityexception, illegalargumentexception, instantiationexception, illegalaccessexception, invocationtargetexception, nosuchmethodexception{
field[] fields = null;
fields = clazz.getdeclaredfields();
return fields;
}
/**
* 根据字符串得到setter格式的属性
* @param str 需要格式化的属性
* @return
*/
public string getsetterstr(string str){
string info = null;
string strvalue = str.substring(0,1).touppercase();
info = "set"+strvalue+str.substring(1,str.length());
return info;
}
/**
* 把setxx还原为xx
* @param str
* @return
*/
public string setsetstr(string str){
string info = null;
string strvalue = str.substring(3,str.length());
string lower = strvalue.substring(0).tolowercase().substring(0,1);
info = lower+str.substring(4,str.length());
return info;
}
/**
* 得到类中的方法
* @param clazz 需要的得到方法的类
* @return
*/
public method[] getmethodsarray(class clazz){
method[] methods = clazz.getmethods();
return methods;
}
/**
* 根据list<map>实例化构造函数
* @param listmap
* @param clazz
* @param tablename 数据库名称
* @return
* @throws nosuchmethodexception
* @throws invocationtargetexception
* @throws securityexception
* @throws illegalargumentexception
* @throws illegalaccessexception
* @throws instantiationexception
*/
@suppresswarnings({ "unchecked" })
public list<object> getlistbymap(list<map<string,object>> listmap,class clazz,string tablename) throws instantiationexception, illegalaccessexception, illegalargumentexception, securityexception, invocationtargetexception, nosuchmethodexception{
list<object> listlast = new arraylist<object>();
list<string> metalist = getmetadatacloumname.getcloumnamelist(tablename);
iterator<map<string,object>> it = listmap.iterator();
while(it.hasnext()){
map<string,object> map = it.next();
iterator<string> iitt = metalist.iterator();
while(iitt.hasnext()){
string info = iitt.next();
this.getobjectarrays(map.get(info));
}
system.out.println("调用反射："+this.cl.length+" "+this.ob.length);
object tobj = this.getclassnewinstance(clazz).getclass().getconstructor(this.cl).newinstance(this.ob);
listlast.add(tobj);
this.setnulltoarrays();
}
return listlast;
}
public static void main(string[] args) {
getnewinstances ge = new getnewinstances();
system.out.println(ge.getsetterstr("namespace")=="setnamespace");
system.out.println("1a"=="1a");
system.out.println(ge.setsetstr("setnamespace"));
}
}