FastJson 的使用

FastJson 的使用

FastJSOn是阿里巴巴开源的JSON处理工具，包括“序列化”和“反序列化”两部分，它具备如下特征：

速度最快，测试表明，fastjson具有极快的性能，超越任其他的java json parser。包括自称最快的jackson。 功能强大，完全支持java bean、集合、Map、日期、Enum，支持范型，支持自省。 无依赖，能够直接运行在Java SE 5.0以上版本 支持Android。 开源 (Apache 2.0)

既然速度快，当然要体验一下。更何况是国产货，当然要支持了。测试一下,以后在项目里使用...

要使用 JSON.  要引入fastjson 包

看代码：

package com.json.fastjson; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.TypeReference; import com.json.bean.Person; /* * 利用 fastjson 进行转换和解析数据 */ public class FastjsonClass { public static void main(String[] args) { //method1(); //method2(); //method3(); method4(); //method5(); //method6(); method7(); } static void method1(){ System.out.println("将json字符串转化成JavaBean对象"); Person person = new Person("1","fastjson",1); //将javaBean 对象 String jsonString = JSON.toJSONString(person); System.out.println(jsonString); //将json字符串转化成JavaBean对象 person =JSON.parseObject(jsonString,Person.class); System.out.println(person.toString()); System.out.println("将json字符串转化成JavaBean对象"); } static void method2(){ System.out.println("将json字符串转化成List<JavaBean>对象"); Person person1 = new Person("1","fastjson1",1); Person person2 = new Person("2","fastjson2",2); List<Person> persons = new ArrayList<Person>(); persons.add(person1); persons.add(person2); String jsonString = JSON.toJSONString(persons); System.out.println("将json字符串转化成List<JavaBean>对象"+jsonString); //进行json解析 List<Person> persons2 = JSON.parseArray(jsonString,Person.class); System.out.println("person1解析后的值:"+persons2.get(0).toString()); System.out.println("person2解析后的值:"+persons2.get(1).toString()); System.out.println("将json字符串转化成List<JavaBean>对象完成"); } static void method3(){ System.out.println("将json字符串转化成List<String>对象"); List<String> list = new ArrayList<String>(); list.add("fastjson1"); list.add("fastjson2"); list.add("fastjson3"); String jsonString = JSON.toJSONString(list); System.out.println("json转换后:"+jsonString); //解析json List<String> list2 = JSON.parseObject(jsonString,new TypeReference<List<String>>(){}); System.out.println(list2.get(0)+"::"+list2.get(1)+"::"+list2.get(2)); System.out.println("将json字符串转化成List<String>对象成功"); } static void method4(){ System.out.println("将json字符串转化成List<Map<String,Object>>对象"); Map<String,Object> map = new HashMap<String,Object>(); map.put("key1", "value1"); map.put("key2", "value2"); Map<String,Object> map2 = new HashMap<String,Object>(); map2.put("key1", 1); map2.put("key2", 2); List<Map<String,Object>> list = new ArrayList<Map<String,Object>>(); list.add(map); list.add(map2); String jsonString = JSON.toJSONString(list); System.out.println("json转化后:"+jsonString); //解析json数据 List<Map<String,Object>> list2 = JSON.parseObject(jsonString,new TypeReference<List<Map<String,Object>>>(){}); System.out.println("List<Map>解析后: "+list2); System.out.println("map的key1值:ֵ"+list2.get(0).get("key1")); System.out.println("map的key2值:"+list2.get(0).get("key2")); System.out.println("map2的key1值:ֵ"+list2.get(1).get("key1")); System.out.println("map2的key2值:ֵ"+list2.get(1).get("key2")); } static void method5(){ System.out.println("将json字符串转化成map(string,List<JavaBean>)对象"); Person person1 = new Person("1","fastjson1",1); Person person2 = new Person("2","fastjson2",2); List<Person> persons = new ArrayList<Person>(); persons.add(person1); persons.add(person2); String jsonString = JSON.toJSONString(persons); System.out.println("map(string,List<JavaBean>):"+jsonString); Map<String,String> map = new HashMap<String, String>(); map.put("key1", jsonString); String json = JSON.toJSONString(map,true); System.out.println(json); for (String key : map.keySet()) { //System.out.println(key+":"+map.get(key)); //进行json解析 List<Person> persons2 = JSON.parseArray(map.get(key),Person.class); System.out.println("person1解析后的值:"+persons2.get(0).toString()); System.out.println("person2解析后的值:"+persons2.get(1).toString()); } } static void method6(){ Map<String,String> map = new HashMap<String, String>(); map.put("a",new String("hhh")); map.put("b",new String("aaa")); map.put("c",new String("ggg")); String json = JSON.toJSONString(map,true); System.out.println(json); //JSON -> Map Map<String,String> map1 = (Map<String,String>)JSON.parse(json); for (String key : map1.keySet()) { System.out.println(key+":"+map1.get(key)); } } static void method7(){ System.out.println("将json字符串转化成Map<string,List<Map<string, string>>对象"); Map<String,String> map = new HashMap<String, String>(); map.put("key1", "aaa"); map.put("key2", "bbb"); map.put("key3", "ccc"); /*Person person1 = new Person("1","fastjson1",1); Person person2 = new Person("2","fastjson2",2);*/ //String json = JSON.toJSONString(map,true); Map<String,String> mapk = new HashMap<String, String>(); mapk.put("key1", "a1a"); mapk.put("key2", "b2b"); mapk.put("key3", "c3c"); /*Person person1 = new Person("1","fastjson1",1); Person person2 = new Person("2","fastjson2",2);*/ //String json1 = JSON.toJSONString(mapk,true); List<Map<String, String>> persons = new ArrayList<Map<String, String>>(); persons.add(map); persons.add(mapk); String jsonString = JSON.toJSONString(persons); System.out.println("List<Map>:"+jsonString); Map<String,String> map1 = new HashMap<String, String>(); map1.put("table1",jsonString); map1.put("table2", jsonString); String jsonString1 = JSON.toJSONString(map1); System.out.println("map<List<Map>>:"+jsonString1); Map<String,String> map2 = (Map<String,String>)JSON.parse(jsonString1); for (String key : map2.keySet()) { //System.out.println(key+":"+map.get(key)); //进行json解析 String listparse = map2.get(key); System.out.println("List<Map>:"+listparse); List<Map<String, Object>> list2 = JSON.parseObject(listparse,new TypeReference<List<Map<String,Object>>>(){}); System.out.println("List<Map>转换后:"+list2); for(int i = 0; i < list2.size(); i++){ //System.out.println("map的key1值:ֵ"+list2.get(i).get("key1")); for(String key1:list2.get(i).keySet()){ System.out.println(key1+":"+list2.get(i).get(key1)); } } } } }

代码：

package com.json.bean; public class Person { private String id ; private String name; private int age ; public Person(){ } public Person(String id,String name,int age){ this.id=id; this.name=name; this.age=age; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "解析json字符串后获取的person对象：id的值是" + id + ", name的值是" + name + ", age的值是" + age + ""; } }

public static void method9(){ Map<String, List<TreeMap<String, Object>>> dataMap = new HashMap<String, List<TreeMap<String, Object>>>(); // 表1 dataMap.put("table1", getDataList(1)); // 表2 dataMap.put("table2", getDataList(2)); String jsonString = JSON.toJSONString(dataMap); System.out.println(jsonString); //JSONObject jsonObject = JSON.parseObject(jsonString); @SuppressWarnings("unchecked") Map<String, List<TreeMap<String, Object>>> parse = (Map<String, List<TreeMap<String, Object>>>) JSON.parse(jsonString); Map<String, List<TreeMap<String, Object>>> a = parse; for(String key: a.keySet()){ System.out.println(key); List<TreeMap<String, Object>> as = a.get(key); System.out.println(as.get(0)); } /* for (String table : jsonObject.keySet()) { System.out.println("表名：" + table); JSONArray jsonArray = jsonObject.getJSONArray(table); for (int i = 0; i < jsonArray.size(); i++) { JSONObject keyValue = jsonArray.getJSONObject(i); for (String key : keyValue.keySet()) { System.out.println("字段：" + key + keyValue.get(key)); } } }*/ } private static List<TreeMap<String, Object>> getDataList(int index) { List<TreeMap<String, Object>> dataList = new ArrayList<TreeMap<String,Object>>(); TreeMap<String, Object> keyValue = new TreeMap<String, Object>(); keyValue.put("index", Integer.toString(index)); keyValue.put("status", new Integer(index)); dataList.add(keyValue); return dataList; }

wangxiaoming 认证博客专家 架构 Spring Boot Redis 博客是很好的总结和记录工具，如果有问题，来不及回复，关注微信公众号：程序员开发者社区，获取我的联系方式，向我提问，也可以给我发送邮件,联系 1275801617@qq.com