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一下三个类：
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
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
*/
@Test
publicvoid test4_JSONArrayToJSONStr() {
// 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);
}
studentName: lily: studentAge: 12
studentName: lucy: studentAge: 15
studentName: lily: studentAge: 12
studentName: lucy: studentAge: 15
[{"studentAge":12,"studentName":"lily"},{"studentAge":15,"studentName":"lucy"}]
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
*/
@Test
publicvoid test5_ComplexJSONStrToJSONObject() {
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
*/
@Test
publicvoid test6_JSONObjectToComplexJSONStr() {
// 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
*/
@Test
publicvoid test7_JSONStrToJavaBeanObj() {
//第一种方式
JSONObject jsonObject = JSONObject.parseObject(JSON_OBJ_STR);
String studentName = jsonObject.getString("studentName");
Integer studentAge = jsonObject.getInteger("studentAge");
//Student student = newStudent(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
*/
@Test
publicvoid test8_JavaBeanObjToJSONStr() {
Student student = new Student("lily", 12);
String jsonString = JSONObject.toJSONString(student);
System.out.println(jsonString);
}
Student{studentName='lily',studentAge=12}
{"studentAge":12,"studentName":"lily"}
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
*/
@Test
publicvoid test9_JSONStrToJavaBeanList() {
//第一种方式
JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR);
//遍历JSONArray
List<Student> students = newArrayList<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
*/
@Test
publicvoid test10_JavaBeanListToJSONStr() {
Student student = new Student("lily", 12);
Student studenttwo = new Student("lucy", 15);
List<Student> students = newArrayList<Student>();
students.add(student);
students.add(studenttwo);
String jsonString = JSONArray.toJSONString(students);
System.out.println(jsonString);
}
students: [Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]
studentList: [Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]
studentList1: [Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]
[{"studentAge":12,"studentName":"lily"},{"studentAge":15,"studentName":"lucy"}]
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
*/
@Test
publicvoid test11_ComplexJSONStrToJavaBean(){
//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
*/
@Test
publicvoid test12_JavaBeanToComplexJSONStr(){
//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);
}
students: [Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]
studentList: [Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]
studentList1: [Student{studentName='lily', studentAge=12}, Student{studentName='lucy',studentAge=15}]
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
*/
@Test
publicvoid test13_JavaBeanToJSONObject(){
//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
*/
@Test
publicvoid test14_JSONObjectToJavaBean(){
//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(), newTypeReference<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);
}
{"studentAge":12,"studentName":"lily"}
{"studentAge":12,"studentName":"lily"}
Student{studentName='lily',studentAge=12}
Student{studentName='lily', studentAge=12}
2.3.2.JavaList与JsonArray之间的转换
/**
* JavaList到JsonArray的转换
*/
@Test
publicvoid test15_JavaListToJsonArray() {
//已知JavaList
Student student = new Student("lily", 12);
Student studenttwo = new Student("lucy", 15);
List<Student> students = newArrayList<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
*/
@Test
publicvoid test16_JsonArrayToJavaList() {
//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(),
newTypeReference<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);
}
[{"studentAge":12,"studentName":"lily"},{"studentAge":15,"studentName":"lucy"}]
[{"studentAge":12,"studentName":"lily"},{"studentAge":15,"studentName":"lucy"}]
[Student{studentName='lily',studentAge=12}, Student{studentName='lucy', studentAge=15}]
[Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]
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
*/
@Test
publicvoid test17_ComplexJavaBeanToJSONObject() {
//已知复杂JavaBean_obj
Student student = new Student("lily", 12);
Student studenttwo = new Student("lucy", 15);
List<Student> students = newArrayList<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
*/
@Test
publicvoid test18_ComplexJSONObjectToJavaBean() {
//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(), newTypeReference<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);
}
{"teacherAge":27,"teacherName":"crystall","course":{"courseName":"english","code":1270},"students":[{"studentAge":12,"studentName":"lily"},{"studentAge":15,"studentName":"lucy"}]}
{"teacherAge":27,"teacherName":"crystall","course":{"courseName":"english","code":1270},"students":[{"studentAge":12,"studentName":"lily"},{"studentAge":15,"studentName":"lucy"}]}
Teacher{teacherName='crystall',teacherAge=27, course=Course{courseName='english', code=1270},students=[Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]}
Teacher{teacherName='crystall',teacherAge=27, course=Course{courseName='english', code=1270},students=[Student{studentName='lily', studentAge=12},Student{studentName='lucy', studentAge=15}]}