fastjson簡介
Fastjson是一個Java語言編寫的高性能功能完善的JSON庫。它采用一種“假定有序快速匹配”的算法,把JSON Parse的性能提升到極致,是目前Java語言中最快的JSON庫。Fastjson接口簡單易用,已經被廣泛使用在緩存序列化、協議交互、Web輸出、Android客戶端等多種應用場景
1.前言
1.1.FastJson的介紹:
JSON協議使用方便,越來越流行,JSON的處理器有很多,這里我介紹一下FastJson,FastJson是阿里的開源框架,被不少企業使用,是一個極其優秀的Json框架,Github地址: FastJson
1.2.FastJson的特點:
1.FastJson數度快,無論序列化和反序列化,都是當之無愧的fast
2.功能強大(支持普通JDK類包括任意Java Bean Class、Collection、Map、Date或enum)
3.零依賴(沒有依賴其它任何類庫)
1.3.FastJson的簡單說明:
FastJson對於json格式字符串的解析主要用到了下面三個類:
1.JSON:fastJson的解析器,用於JSON格式字符串與JSON對象及javaBean之間的轉換
2.JSONObject:fastJson提供的json對象
3.JSONArray:fastJson提供json數組對象
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2.FastJson的用法
首先定義三個json格式的字符串
//json字符串-簡單對象型 private static final String JSON_OBJ_STR = "{\"studentName\":\"lily\",\"studentAge\":12}"; //json字符串-數組類型 private static final String JSON_ARRAY_STR = "[{\"studentName\":\"lily\",\"studentAge\":12},{\"studentName\":\"lucy\",\"studentAge\":15}]"; //復雜格式json字符串 private static final String COMPLEX_JSON_STR = "{\"teacherName\":\"crystall\",\"teacherAge\":27,\"course\":{\"courseName\":\"english\",\"code\":1270},\"students\":[{\"studentName\":\"lily\",\"studentAge\":12},{\"studentName\":\"lucy\",\"studentAge\":15}]}";
2.1.JSON格式字符串與JSON對象之間的轉換
2.1.1.json字符串-簡單對象型與JSONObject之間的轉換
/** * json字符串-簡單對象型到JSONObject的轉換 */ @Test public void testJSONStrToJSONObject() { JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); System.out.println("studentName: " + jsonObject.getString("studentName") + ":" + " studentAge: " + jsonObject.getInteger("studentAge")); } /** * JSONObject到json字符串-簡單對象型的轉換 */ @Test public void testJSONObjectToJSONStr() { //已知JSONObject,目標要轉換為json字符串 JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); // 第一種方式 String jsonString = JSONObject.toJSONString(jsonObject); // 第二種方式 //String jsonString = jsonObject.toJSONString(); System.out.println(jsonString); }
2.1.2.json字符串(數組類型)與JSONArray之間的轉換
/** * json字符串-數組類型到JSONArray的轉換 */ @Test public void testJSONStrToJSONArray() { JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); //遍歷方式1 int size = jsonArray.size(); for (int i = 0; i < size; i++) { JSONObject jsonObject = jsonArray.getJSONObject(i); System.out.println("studentName: " + jsonObject.getString("studentName") + ":" + " studentAge: " + jsonObject.getInteger("studentAge")); } //遍歷方式2 for (Object obj : jsonArray) { JSONObject jsonObject = (JSONObject) obj; System.out.println("studentName: " + jsonObject.getString("studentName") + ":" + " studentAge: " + jsonObject.getInteger("studentAge")); } } /** * JSONArray到json字符串-數組類型的轉換 */ @Test public void testJSONArrayToJSONStr() { //已知JSONArray,目標要轉換為json字符串 JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); //第一種方式 String jsonString = JSONArray.toJSONString(jsonArray); // 第二種方式 //String jsonString = jsonArray.toJSONString(jsonArray); System.out.println(jsonString); }
2.1.3.復雜json格式字符串與JSONObject之間的轉換
/** * 復雜json格式字符串到JSONObject的轉換 */ @Test public void testComplexJSONStrToJSONObject() { JSONObject jsonObject = JSONObject.parseObject(COMPLEX_JSON_STR); String teacherName = jsonObject.getString("teacherName"); Integer teacherAge = jsonObject.getInteger("teacherAge"); System.out.println("teacherName: " + teacherName + " teacherAge: " + teacherAge); JSONObject jsonObjectcourse = jsonObject.getJSONObject("course"); //獲取JSONObject中的數據 String courseName = jsonObjectcourse.getString("courseName"); Integer code = jsonObjectcourse.getInteger("code"); System.out.println("courseName: " + courseName + " code: " + code); JSONArray jsonArraystudents = jsonObject.getJSONArray("students"); //遍歷JSONArray for (Object object : jsonArraystudents) { JSONObject jsonObjectone = (JSONObject) object; String studentName = jsonObjectone.getString("studentName"); Integer studentAge = jsonObjectone.getInteger("studentAge"); System.out.println("studentName: " + studentName + " studentAge: " + studentAge); } } /** * 復雜JSONObject到json格式字符串的轉換 */ @Test public void testJSONObjectToComplexJSONStr() { //復雜JSONObject,目標要轉換為json字符串 JSONObject jsonObject = JSONObject.parseObject(COMPLEX_JSON_STR); //第一種方式 //String jsonString = JSONObject.toJSONString(jsonObject); //第二種方式 String jsonString = jsonObject.toJSONString(); System.out.println(jsonString); }
2.2.JSON格式字符串與javaBean之間的轉換
2.2.1.json字符串-簡單對象型與javaBean之間的轉換
/** * json字符串-簡單對象到JavaBean之間的轉換 */ @Test public void testJSONStrToJavaBeanObj() { //第一種方式 JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); String studentName = jsonObject.getString("studentName"); Integer studentAge = jsonObject.getInteger("studentAge"); //Student student = new Student(studentName, studentAge); //第二種方式,使用TypeReference<T>類,由於其構造方法使用protected進行修飾,故創建其子類 //Student student = JSONObject.parseObject(JSON_OBJ_STR, new TypeReference<Student>() {}); //第三種方式,使用Gson的思想 Student student = JSONObject.parseObject(JSON_OBJ_STR, Student.class); System.out.println(student); } /** * JavaBean到json字符串-簡單對象的轉換 */ @Test public void testJavaBeanObjToJSONStr() { Student student = new Student("lily", 12); String jsonString = JSONObject.toJSONString(student); System.out.println(jsonString); }
2.2.2.json字符串-數組類型與javaBean之間的轉換
/** * json字符串-數組類型到JavaBean_List的轉換 */ @Test public void testJSONStrToJavaBeanList() { //第一種方式 JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); //遍歷JSONArray List<Student> students = new ArrayList<Student>(); Student student = null; for (Object object : jsonArray) { JSONObject jsonObjectone = (JSONObject) object; String studentName = jsonObjectone.getString("studentName"); Integer studentAge = jsonObjectone.getInteger("studentAge"); student = new Student(studentName,studentAge); students.add(student); } System.out.println("students: " + students); //第二種方式,使用TypeReference<T>類,由於其構造方法使用protected進行修飾,故創建其子類 List<Student> studentList = JSONArray.parseObject(JSON_ARRAY_STR, new TypeReference<ArrayList<Student>>() {}); System.out.println("studentList: " + studentList); //第三種方式,使用Gson的思想 List<Student> studentList1 = JSONArray.parseArray(JSON_ARRAY_STR, Student.class); System.out.println("studentList1: " + studentList1); } /** * JavaBean_List到json字符串-數組類型的轉換 */ @Test public void testJavaBeanListToJSONStr() { Student student = new Student("lily", 12); Student studenttwo = new Student("lucy", 15); List<Student> students = new ArrayList<Student>(); students.add(student); students.add(studenttwo); String jsonString = JSONArray.toJSONString(students); System.out.println(jsonString); }
2.2.3.復雜json格式字符串與與javaBean之間的轉換
/** * 復雜json格式字符串到JavaBean_obj的轉換 */ @Test public void testComplexJSONStrToJavaBean(){ //第一種方式,使用TypeReference<T>類,由於其構造方法使用protected進行修飾,故創建其子類 Teacher teacher = JSONObject.parseObject(COMPLEX_JSON_STR, new TypeReference<Teacher>() {}); System.out.println(teacher); //第二種方式,使用Gson思想 Teacher teacher1 = JSONObject.parseObject(COMPLEX_JSON_STR, Teacher.class); System.out.println(teacher1); } /** * 復雜JavaBean_obj到json格式字符串的轉換 */ @Test public void testJavaBeanToComplexJSONStr(){ //已知復雜JavaBean_obj Teacher teacher = JSONObject.parseObject(COMPLEX_JSON_STR, new TypeReference<Teacher>() {}); String jsonString = JSONObject.toJSONString(teacher); System.out.println(jsonString); }
2.3.javaBean與json對象間的之間的轉換
2.3.1.簡單javaBean與json對象之間的轉換
/** * 簡單JavaBean_obj到json對象的轉換 */ @Test public void testJavaBeanToJSONObject(){ //已知簡單JavaBean_obj Student student = new Student("lily", 12); //方式一 String jsonString = JSONObject.toJSONString(student); JSONObject jsonObject = JSONObject.parseObject(jsonString); System.out.println(jsonObject); //方式二 JSONObject jsonObject1 = (JSONObject) JSONObject.toJSON(student); System.out.println(jsonObject1); } /** * 簡單json對象到JavaBean_obj的轉換 */ @Test public void testJSONObjectToJavaBean(){ //已知簡單json對象 JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); //第一種方式,使用TypeReference<T>類,由於其構造方法使用protected進行修飾,故創建其子類 Student student = JSONObject.parseObject(jsonObject.toJSONString(), new TypeReference<Student>() {}); System.out.println(student); //第二種方式,使用Gson的思想 Student student1 = JSONObject.parseObject(jsonObject.toJSONString(), Student.class); System.out.println(student1); }
2.3.2.JavaList與JsonArray之間的轉換
/** * JavaList到JsonArray的轉換 */ @Test public void testJavaListToJsonArray() { //已知JavaList Student student = new Student("lily", 12); Student studenttwo = new Student("lucy", 15); List<Student> students = new ArrayList<Student>(); students.add(student); students.add(studenttwo); //方式一 String jsonString = JSONArray.toJSONString(students); JSONArray jsonArray = JSONArray.parseArray(jsonString); System.out.println(jsonArray); //方式二 JSONArray jsonArray1 = (JSONArray) JSONArray.toJSON(students); System.out.println(jsonArray1); } /** * JsonArray到JavaList的轉換 */ @Test public void testJsonArrayToJavaList() { //已知JsonArray JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); //第一種方式,使用TypeReference<T>類,由於其構造方法使用protected進行修飾,故創建其子類 ArrayList<Student> students = JSONArray.parseObject(jsonArray.toJSONString(), new TypeReference<ArrayList<Student>>() {}); System.out.println(students); //第二種方式,使用Gson的思想 List<Student> students1 = JSONArray.parseArray(jsonArray.toJSONString(), Student.class); System.out.println(students1); }
2.3.3.復雜JavaBean_obj與json對象之間的轉換
/** * 復雜JavaBean_obj到json對象的轉換 */ @Test public void testComplexJavaBeanToJSONObject() { //已知復雜JavaBean_obj Student student = new Student("lily", 12); Student studenttwo = new Student("lucy", 15); List<Student> students = new ArrayList<Student>(); students.add(student); students.add(studenttwo); Course course = new Course("english", 1270); Teacher teacher = new Teacher("crystall", 27, course, students); //方式一 String jsonString = JSONObject.toJSONString(teacher); JSONObject jsonObject = JSONObject.parseObject(jsonString); System.out.println(jsonObject); //方式二 JSONObject jsonObject1 = (JSONObject) JSONObject.toJSON(teacher); System.out.println(jsonObject1); } /** * 復雜json對象到JavaBean_obj的轉換 */ @Test public void testComplexJSONObjectToJavaBean() { //已知復雜json對象 JSONObject jsonObject = JSONObject.parseObject(COMPLEX_JSON_STR); //第一種方式,使用TypeReference<T>類,由於其構造方法使用protected進行修飾,故創建其子類 Teacher teacher = JSONObject.parseObject(jsonObject.toJSONString(), new TypeReference<Teacher>() {}); System.out.println(teacher); //第二種方式,使用Gson的思想 Teacher teacher1 = JSONObject.parseObject(jsonObject.toJSONString(), Teacher.class); System.out.println(teacher1); }
3.源碼
本篇博客的源碼都在我的Github上,FastJsonDemo,歡迎大家Fork and Star!
Maven引入
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.37</version>
</dependency>
常用api
1. 將對象序列化成json字符串
String com.alibaba.fastjson.JSON.toJSONString(Object object)
2. 將json字符串反序列化成對象
<T> Project com.alibaba.fastjson.JSON.parseObject(String text, Class<T> clazz)
3. 將json字符串反序列化成JSON對象
JSONObject com.alibaba.fastjson.JSON.parseObject(String text)
4.根據key 得到json中的json數組
JSONArray com.alibaba.fastjson.JSONObject.getJSONArray(String key)
5. 根據下標拿到json數組的json對象
JSONObject com.alibaba.fastjson.JSONArray.getJSONObject(int index)
6.. 根據key拿到json的字符串值
String com.alibaba.fastjson.JSONObject.getString(String key)
7. 根據key拿到json的int值
int com.alibaba.fastjson.JSONObject.getIntValue(String key)
8. 根據key拿到json的boolean值
boolean com.alibaba.fastjson.JSONObject.getBooleanValue(String key)
實例說明
Project類
package com.json; import java.util.List; public class Project { String pjName; boolean waibao; public boolean isWaibao() { return waibao; } public void setWaibao(boolean waibao) { this.waibao = waibao; } List<Factory> l_factory; //List<Worker> worker; public String getPjName() { return pjName; } public void setPjName(String pjName) { this.pjName = pjName; } public List<Factory> getL_factory() { return l_factory; } public void setL_factory(List<Factory> l_factory) { this.l_factory = l_factory; } }
Factory類
package com.json; import java.util.List; public class Factory { String fcName; List<Worker> l_worker; public String getFcName() { return fcName; } public void setFcName(String fcName) { this.fcName = fcName; } public List<Worker> getL_worker() { return l_worker; } public void setL_worker(List<Worker> l_worker) { this.l_worker = l_worker; } }
Worker類
package com.json; public class Worker { String name; String sex; int age; 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 String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } }
測試類
package com.json; import java.util.ArrayList; import java.util.List; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONArray; import com.alibaba.fastjson.JSONObject; public class TestFastJson { public static void main(String args[]) { TestFastJson tfj = new TestFastJson(); Project prj = tfj.init(); String json= tfj.getJsonString(prj); System.out.println("json="+json); //json={"l_factory":[{"fcName":"東軟","l_worker":[{"age":30,"name":"喬佳飛","sex":"男"},{"age":25,"name":"李帥飛","sex":"女"}]},{"fcName":"亞信","l_worker":[{"age":26,"name":"王新峰","sex":"男"},{"age":0}]}],"pjName":"接口自動化","waibao":true} System.out.println("waibao="+tfj.getJsonValueObj(json, "waibao", Boolean.class)); //waibao=true JSONArray array = (JSONArray) tfj.getJsonValueObj(json, "l_factory", JSONArray.class); System.out.println("array="+array.toString()); //array=[{"fcName":"東軟","l_worker":[{"sex":"男","name":"喬佳飛","age":30},{"sex":"女","name":"李帥飛","age":25}]},{"fcName":"亞信","l_worker":[{"sex":"男","name":"王新峰","age":26},{"age":0}]}] String jsonArr = tfj.getJsonArrayValue(array, 0, "fcName"); System.out.println("fcName="+jsonArr); //fcName=東軟 JSONArray array2 = tfj.getJsonArrayValueIsArray(array, 0, "l_worker"); System.out.println("array2="+array2.toString()); //array2=[{"sex":"男","name":"喬佳飛","age":30},{"sex":"女","name":"李帥飛","age":25}] String json2 = tfj.getJsonArrayValue(array2, 0); System.out.println("json2="+json2); //json2={"sex":"男","name":"喬佳飛","age":30} /*以下輸出 name=喬佳飛 sex=男 age=30 jsonArr2=男 * */ System.out.println("name="+tfj.getJsonValueObj(json2, "name", String.class)); System.out.println("sex="+tfj.getJsonValueObj(json2, "sex", String.class)); System.out.println("age="+tfj.getJsonValueObj(json2, "age", Integer.class)); String jsonArr2 = tfj.getJsonArrayValue(array2, 0, "sex"); System.out.println("jsonArr2="+jsonArr2); /*以下輸出 接口自動化 東軟 喬佳飛 */ System.out.println(tfj.getJsonValue(json)); System.out.println(tfj.getJsonValue(json,"l_factory")); System.out.println(tfj.getJsonValue(json,"l_factory","l_worker")); } public static void main1(String args[]) { TestFastJson tfj = new TestFastJson(); Project prj = tfj.init(); String json= tfj.getJsonString(prj); prj.setPjName("序列化后修改pjname"); System.out.println(prj.getPjName());//序列化后修改pjname Project po = JSON.parseObject(json,Project.class); System.out.println(po.getPjName());//接口自動化 } public void tt(Class clazz) { System.out.println(clazz.getSimpleName()); if(clazz.getName().equals("String")) { System.out.println("stringllala"); } } public Project init() { Project pj = new Project(); Factory ft1 = new Factory(); Factory ft2 = new Factory(); Worker wk1 = new Worker(); wk1.setName("喬佳飛"); wk1.setSex("男"); wk1.setAge(30); Worker wk2 = new Worker(); wk2.setName("李帥飛"); wk2.setSex("女"); wk2.setAge(25); Worker wk3 = new Worker(); wk3.setName("魏曉博"); wk3.setSex("男"); wk3.setAge(27); Worker wk4 = new Worker(); wk3.setName("王新峰"); wk3.setSex("男"); wk3.setAge(26); List<Worker> workers1 = new ArrayList<Worker>(); workers1.add(wk1); workers1.add(wk2); List<Worker> workers2 = new ArrayList<Worker>(); workers2.add(wk3); workers2.add(wk4); ft1.setFcName("東軟"); ft1.setL_worker(workers1); ft2.setFcName("亞信"); ft2.setL_worker(workers2); List<Factory> factorys = new ArrayList<Factory>(); factorys.add(ft1); factorys.add(ft2); pj.setPjName("接口自動化"); pj.setWaibao(true); pj.setL_factory(factorys); return pj; } /** * * 將對象轉換成json * */ public String getJsonString(Object obj) { String json= JSON.toJSONString(obj); return json; } /** * 根據key得到json的value * */ public String getJsonValue(String json) { JSONObject jo = JSON.parseObject(json); String value = jo.getString("pjName"); return value; } /** * 根據key得到json的集合 * */ public JSONArray getJsonArray(String json, String key) { JSONObject jo = JSON.parseObject(json); JSONArray array = jo.getJSONArray(key); return array; } /** * 根據下標得到json數組的值 * */ public String getJsonArrayValue(JSONArray array, int index) { JSONObject jo_fc = array.getJSONObject(index); String json = jo_fc.toJSONString(); return json; } /** * 根據下標得到json數組的值,再根據key得到該值的value,該值類型是String * */ public String getJsonArrayValue(JSONArray array, int index, String key) { JSONObject jo_fc = array.getJSONObject(index); String value = jo_fc.getString(key); return value; } /** * 根據下標得到json數組的值,再根據key得到該值的value,該值類型是JSONArray * */ public JSONArray getJsonArrayValueIsArray(JSONArray array, int index, String key) { JSONObject jo_fc = array.getJSONObject(index); JSONArray arrayNew = jo_fc.getJSONArray(key); return arrayNew; } /** * 根據對象的類型,自動識別獲取該對象的值 * */ public Object getJsonValueObj(String json, String key, Class clazz) { JSONObject jo = JSON.parseObject(json); if(clazz.getSimpleName().equals("String")) { String value = jo.getString(key); return value; }else if(clazz.getSimpleName().equals("Integer")) { Integer value = jo.getInteger(key); return value; }else if (clazz.getSimpleName().equals("Boolean")) { Boolean value = jo.getBoolean(key); return value; }else if(clazz.getSimpleName().equals("JSONArray")) { JSONArray array = jo.getJSONArray(key); return array; } else { return "error, 暫不支持的類型:"+clazz.toString(); } } public String getJsonValue(String json, String key) { JSONObject jo = JSON.parseObject(json); JSONArray array = jo.getJSONArray(key); JSONObject jo_fc = array.getJSONObject(0); String value = jo_fc.getString("fcName"); return value; } public String getJsonValue(String json, String key, String keyW) { JSONObject jo = JSON.parseObject(json); JSONArray array = jo.getJSONArray(key); JSONObject jo_fc = array.getJSONObject(0); JSONArray arrayW = jo_fc.getJSONArray(keyW); JSONObject jo_wk = arrayW.getJSONObject(0); String value = jo_wk.getString("name"); int age = jo_wk.getIntValue("age"); //System.out.println(age); return value; } }