高性能JSON框架之FastJson的简单使用

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

    // json字符串-简单对象型

    privatestaticfinal String JSON_OBJ_STR = "{"studentName":"lily","studentAge":12}";

 

    // json字符串-数组类型

    privatestaticfinal String JSON_ARRAY_STR = "[{"studentName":"lily","studentAge":12},{"studentName":"lucy","studentAge":15}]";

 

    // 复杂格式json字符串

    privatestaticfinal 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

 */

@Test

publicvoid test1_JSONStrToJSONObject() {

 

    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

 */

@Test

publicvoid test2_JSONObjectToJSONStr() {

 

    // 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);

 

}

 

studentName:  lily: studentAge:  12

{"studentAge":12,"studentName":"lily"}

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

 */

@Test

publicvoid test3_JSONStrToJSONArray() {

 

    JSONArray jsonArray = JSONArray.parseArray(JSON_ARRAY_STR);

 

    // 遍历方式1

    intsize = jsonArray.size();

    for (inti = 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

 */

@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}]}