java反射实现javabean转json实例代码

objecttojson.java

package com.objecttojson;

import java.lang.reflect.field;
import java.lang.reflect.invocationtargetexception;
import java.lang.reflect.method;
import java.util.arraylist;
import java.util.iterator;

public class objecttojson {

 
 public  static string objlisttojson(arraylist<?> list){
  stringbuilder build=new stringbuilder();
  //迭代器
  iterator<?> iterator=list.iterator();
  build.append("[");
  string separate="";
  while(iterator.hasnext()){
   build.append(separate);
   //object转json字符串
   string str=objtojson(iterator.next());
   build.append(str);
   separate=",";
  }
  build.append("]");
  return build.tostring();
 }

 @suppresswarnings("unchecked")
 public  static string objtojson(object obj){
  stringbuilder build=new stringbuilder();
  build.append("{");
  @suppresswarnings("rawtypes")
  class cla=null;
  try {
   //反射加载类
   cla=class.forname(obj.getclass().getname());
  } catch (classnotfoundexception e) {
   system.out.println(obj.getclass().tostring().concat(" 未找到这个类"));
   e.printstacktrace();
   return null;
  }

  stringbuffer methodname=new stringbuffer();
  //获取java类的变量
  field[] fields=cla.getdeclaredfields();
  string separate="";
  for(field temp:fields){
   build.append(separate);
   build.append("\"");
   build.append(temp.getname());
   build.append("\":");

   methodname.append("get");
   methodname.append(temp.getname().substring(0,1).touppercase());
   methodname.append(temp.getname().substring(1));

   build.append("\"");
   method method=null;
   try {
    //获取java的get方法
    method=cla.getmethod(methodname.tostring());
   } catch (nosuchmethodexception | securityexception e) {
    methodname.setlength(0);
    e.printstacktrace();
   }

   try {
    //执行get方法，获取变量参数的直。
    build.append(method.invoke(obj));
   } catch (illegalaccessexception e) {
    e.printstacktrace();
   } catch (illegalargumentexception e) {
    e.printstacktrace();
   } catch (invocationtargetexception e) {
    e.printstacktrace();
   }

   build.append("\"");
   methodname.setlength(0);
   separate=",";
  }

  build.append("}");
  return build.tostring();
 }
}

 test.java

 

 package com.test;

import java.util.arraylist;

import com.objecttojson.objecttojson;

public class test {
  public static void main(string[] args){
   //数据构建
   arraylist<user> list=getlist();
   //数据转换
   string listjson=objecttojson.objlisttojson((arraylist<?>)list);
   system.out.println("{\"data\":"+listjson+"}");
  }

  public static arraylist<user> getlist(){
   user user00=new user();
   user00.setuserage("27");
   user00.setusername("smart");
   user00.setusersex("man");

   user user01=new user();
   user01.setuserage("27");
   user01.setusername("smart00");
   user01.setusersex("man");

   arraylist<user> list=new arraylist<user>();

   list.add(user00);
   list.add(user01);

   return list;
  }

}
 

 user.java

 

 package com.test;

public class user {
 private string username;
 private string usersex;
 private string userage;

 public string getusername() {
  return username;
 }
 public void setusername(string username) {
  this.username = username;
 }
 public string getusersex() {
  return usersex;
 }
 public void setusersex(string usersex) {
  this.usersex = usersex;
 }
 public string getuserage() {
  return userage;
 }
 public void setuserage(string userage) {
  this.userage = userage;
 }
 

}
 

 测试结果

 

 {"data":[{"username":"smart","usersex":"man","userage":"27"},{"username":"smart00","usersex":"man","userage":"27"}]}