1.前言
1.1.FastJson的介绍:
JSON协议使用方便，越来越流行,JSON的处理器有很多,这里我介绍一下FastJson,FastJson是阿里的开源框架,被不少企业使用,是一个极其优秀的Json框架,Github地址: FastJson
1.2.FastJson的特点:
1.FastJson数度快,无论序列化和反序列化,都是当之无愧的fast
2.功能强大(支持普通JDK类包括任意Java Bean Class、Collection、Map、Date或enum)
3.零依赖(没有依赖其它任何类库)
1.3.FastJson的简单说明:
FastJson对于json格式字符串的解析主要用到了下面三个类：
1.JSON：fastJson的解析器，用于JSON格式字符串与JSON对象及javaBean之间的转换
2.JSONObject：fastJson提供的json对象
3.JSONArray：fastJson提供json数组对象
2.FastJson的用法
首先定义三个json格式的字符串
//json字符串-简单对象型private static final String ?JSON_OBJ_STR = "{\"studentName\":\"lily\",\"studentAge\":12}";//json字符串-数组类型private static final String ?JSON_ARRAY_STR = "[{\"studentName\":\"lily\",\"studentAge\":12},{\"studentName\":\"lucy\",\"studentAge\":15}]";//复杂格式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格式字符串与JSON对象之间的转换
2.1.1.json字符串-简单对象型与JSONObject之间的转换
/** * json字符串-简单对象型到JSONObject的转换 */@Testpublic 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-简单对象型的转换 */@Testpublic void testJSONObjectToJSONStr() { ???//已知JSONObject,目标要转换为json字符串 ???JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); ???// 第一种方式 ???String jsonString = JSONObject.toJSONString(jsonObject); ???// 第二种方式 ???//String jsonString = jsonObject.toJSONString(); ???System.out.println(jsonString);}2.1.2.json字符串(数组类型)与JSONArray之间的转换
/** * json字符串-数组类型到JSONArray的转换 */@Testpublic void testJSONStrToJSONArray() { ???JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); ???//遍历方式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")); ???} ???//遍历方式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-数组类型的转换 */@Testpublic void testJSONArrayToJSONStr() { ???//已知JSONArray,目标要转换为json字符串 ???JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); ???//第一种方式 ???String jsonString = JSONArray.toJSONString(jsonArray); ???// 第二种方式 ???//String jsonString = jsonArray.toJSONString(jsonArray); ???System.out.println(jsonString);}2.1.3.复杂json格式字符串与JSONObject之间的转换
/** * 复杂json格式字符串到JSONObject的转换 */@Testpublic 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"); ????//获取JSONObject中的数据 ???String courseName = jsonObjectcourse.getString("courseName"); ???Integer code = jsonObjectcourse.getInteger("code"); ???System.out.println("courseName: ?" + courseName + " ??code: ?" + code); ???JSONArray jsonArraystudents = jsonObject.getJSONArray("students"); ???//遍历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); ???}}/** * 复杂JSONObject到json格式字符串的转换 */@Testpublic void testJSONObjectToComplexJSONStr() { ??//复杂JSONObject,目标要转换为json字符串 ???JSONObject jsonObject = JSONObject.parseObject(COMPLEX_JSON_STR); ???//第一种方式 ???//String jsonString = JSONObject.toJSONString(jsonObject); ???//第二种方式 ???String jsonString = jsonObject.toJSONString(); ???System.out.println(jsonString);}2.2.JSON格式字符串与javaBean之间的转换
2.2.1.json字符串-简单对象型与javaBean之间的转换
/** * json字符串-简单对象到JavaBean之间的转换 */@Testpublic void testJSONStrToJavaBeanObj() { ???//第一种方式 ???JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); ???String studentName = jsonObject.getString("studentName"); ???Integer studentAge = jsonObject.getInteger("studentAge"); ???//Student student = new Student(studentName, studentAge); ???//第二种方式,使用TypeReference<T>类,由于其构造方法使用protected进行修饰,故创建其子类 ???//Student student = JSONObject.parseObject(JSON_OBJ_STR, new TypeReference<Student>() {}); ???//第三种方式,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-简单对象的转换 */@Testpublic void testJavaBeanObjToJSONStr() { ???Student student = new Student("lily", 12); ???String jsonString = JSONObject.toJSONString(student); ???System.out.println(jsonString);}2.2.2.json字符串-数组类型与javaBean之间的转换
/** * json字符串-数组类型到JavaBean_List的转换 */@Testpublic void testJSONStrToJavaBeanList() { ???//第一种方式 ???JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); ???//遍历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); ???//第二种方式,使用TypeReference<T>类,由于其构造方法使用protected进行修饰,故创建其子类 ???List<Student> studentList = JSONArray.parseObject(JSON_ARRAY_STR, new TypeReference<ArrayList<Student>>() {}); ???System.out.println("studentList: ?" + studentList); ???//第三种方式,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-数组类型的转换 */@Testpublic 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.复杂json格式字符串与与javaBean之间的转换
/** * 复杂json格式字符串到JavaBean_obj的转换 */@Testpublic void testComplexJSONStrToJavaBean(){ ???//第一种方式,使用TypeReference<T>类,由于其构造方法使用protected进行修饰,故创建其子类 ???Teacher teacher = JSONObject.parseObject(COMPLEX_JSON_STR, new TypeReference<Teacher>() {}); ???System.out.println(teacher); ???//第二种方式,使用Gson思想 ???Teacher teacher1 = JSONObject.parseObject(COMPLEX_JSON_STR, Teacher.class); ???System.out.println(teacher1);}/** * 复杂JavaBean_obj到json格式字符串的转换 */@Testpublic void testJavaBeanToComplexJSONStr(){ ???//已知复杂JavaBean_obj ???Teacher teacher = JSONObject.parseObject(COMPLEX_JSON_STR, new TypeReference<Teacher>() {}); ???String jsonString = JSONObject.toJSONString(teacher); ???System.out.println(jsonString);}2.3.javaBean与json对象间的之间的转换
2.3.1.简单javaBean与json对象之间的转换
/** * 简单JavaBean_obj到json对象的转换 */@Testpublic void testJavaBeanToJSONObject(){ ???//已知简单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);}/** * 简单json对象到JavaBean_obj的转换 */@Testpublic void testJSONObjectToJavaBean(){ ???//已知简单json对象 ???JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR); ???//第一种方式,使用TypeReference<T>类,由于其构造方法使用protected进行修饰,故创建其子类 ???Student student = JSONObject.parseObject(jsonObject.toJSONString(), new TypeReference<Student>() {}); ???System.out.println(student); ???//第二种方式,使用Gson的思想 ???Student student1 = JSONObject.parseObject(jsonObject.toJSONString(), Student.class); ???System.out.println(student1);}2.3.2.JavaList与JsonArray之间的转换
/** * JavaList到JsonArray的转换 */@Testpublic 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的转换 */@Testpublic void testJsonArrayToJavaList() { ???//已知JsonArray ???JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR); ???//第一种方式,使用TypeReference<T>类,由于其构造方法使用protected进行修饰,故创建其子类 ???ArrayList<Student> students = JSONArray.parseObject(jsonArray.toJSONString(), ???????????new TypeReference<ArrayList<Student>>() {}); ???System.out.println(students); ???//第二种方式,使用Gson的思想 ???List<Student> students1 = JSONArray.parseArray(jsonArray.toJSONString(), Student.class); ???System.out.println(students1);}2.3.3.复杂JavaBean_obj与json对象之间的转换
/** * 复杂JavaBean_obj到json对象的转换 */@Testpublic void testComplexJavaBeanToJSONObject() { ???//已知复杂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);}/** * 复杂json对象到JavaBean_obj的转换 */@Testpublic void testComplexJSONObjectToJavaBean() { ???//已知复杂json对象 ???JSONObject jsonObject = JSONObject.parseObject(COMPLEX_JSON_STR); ???//第一种方式,使用TypeReference<T>类,由于其构造方法使用protected进行修饰,故创建其子类 ???Teacher teacher = JSONObject.parseObject(jsonObject.toJSONString(), new TypeReference<Teacher>() {}); ???System.out.println(teacher); ???//第二种方式,使用Gson的思想 ???Teacher teacher1 = JSONObject.parseObject(jsonObject.toJSONString(), Teacher.class); ???System.out.println(teacher1);}3.源码
本篇博客的源码都在我的Github上,FastJsonDemo,欢迎大家Fork and Star!
转自：https://segmentfault.com/a/1190000011212806
高性能JSON框架之FastJson的简单使用
原文地址：https://www.cnblogs.com/hzdzkjdxygz/p/8995249.html