基于JAVA中的四种JSON解析方式详解

public class Student {  private int id;  private String name;  private int age;  public int getId() {    return id;  }  public void setId(int 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;  }  public Student(int id, String name, int age) {    super();    this.id = id;    this.name = name;    this.age = age;  }  public Student() {    super();  }  @Override  public String toString() {    return "Student [id=" + id + ", name=" + name + ", age=" + age + "]";  }}

public class Grade {  private int id;  private String name;  private ArrayList<Student> stus;  public Grade(int id, String name, ArrayList<Student> stus) {    super();    this.id = id;    this.name = name;    this.stus = stus;  }  public Grade() {    super();  }  @Override  public String toString() {    return "Grade [id=" + id + ", name=" + name + ", stus=" + stus + "]";  }  public int getId() {    return id;  }  public void setId(int id) {    this.id = id;  }  public String getName() {    return name;  }  public void setName(String name) {    this.name = name;  }  public ArrayList<Student> getStus() {    return stus;  }  public void setStus(ArrayList<Student> stus) {    this.stus = stus;  }}

public class JSONTest {  //解析JSON  @Test  public void test1() throws JSONException{    //对象嵌套数组嵌套对象    String json1="{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘一','age':16}]}";    //数组    String json2="['北京','天津','杭州']";    //1、    //解析第一层---对象    JSONObject jObject1=new JSONObject(json1);    Grade grade=new Grade();    grade.setId(jObject1.getInt("id"));    grade.setName(jObject1.getString("name"));    ArrayList<Student> stus=new ArrayList<>();    grade.setStus(stus);    //解析第二层----数组    JSONArray jsonArray2=jObject1.getJSONArray("stus");    //遍历数组获取元素----对象    for(int i=0;i<jsonArray2.length();i++){      //解析第三层----对象      JSONObject jObject3=jsonArray2.getJSONObject(i);      Student student=new Student(jObject3.getInt("id"), jObject3.getString("name"), jObject3.getInt("age"));      grade.getStus().add(student);    }    System.out.println(grade);    //获取当前对象的所有属性的迭代器对象//   Iterator<String> iterator=jObject1.keys();//   while (iterator.hasNext()) {//     String key = iterator.next();//     System.out.println("属性："+key);//   }    //2、    //获取数组对象    JSONArray jArray=new JSONArray(json2);    ArrayList<String> list=new ArrayList<>();    //遍历获取元素    for(int i=0;i<jArray.length();i++){      //jArray.optString(i);//等价于getXXX      list.add(jArray.getString(i));    }    System.out.println("解析结果："+list);  }  //生成JSON  @Test  public void test2() throws JSONException{    JSONObject jo1=new JSONObject();    jo1.put("id", 1001);    jo1.put("name", "范老");    jo1.put("age", 20);    JSONObject jo2=new JSONObject();    jo2.put("id", 1002);    jo2.put("name", "平平");    jo2.put("age", 19);    JSONArray ja2=new JSONArray();    ja2.put(jo1);    ja2.put(jo2);    JSONObject jo3=new JSONObject();    jo3.put("id", 11);    jo3.put("name", "JAVAEE-1704");    jo3.put("stus",ja2);        String json=jo3.toString();    System.out.println(json);  }}

public class GSONTest {  //解析  @Test  public void test1() {    // 对象嵌套数组嵌套对象    String json1 = "{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘一','age':16}]}";    // 数组    String json2 = "['北京','天津','杭州']";    Gson gson=new Gson();    //1、    //解析对象：第一个参数：待解析的字符串 第二个参数结果数据类型的Class对象    Grade grade=gson.fromJson(json1, Grade.class);    System.out.println(grade);    //2、    //解析数组要求使用Type    ArrayList<String> list=gson.fromJson(json2,         new TypeToken<ArrayList<String>>(){}.getType());    System.out.println(list);  }  //生成  @Test  public void test2(){    ArrayList<Student> list=new ArrayList<>();    for(int i=1;i<3;i++){      list.add(new Student(101+i, "码子", 20+i));    }    Grade grade=new Grade(100001,"张三", list);    Gson gson=new Gson();    //将对象转换为诶JSON格式字符串    String json=gson.toJson(grade);    System.out.println(json);  }}

public class FASTJson {  //解析  @Test  public void test1() {    // 对象嵌套数组嵌套对象    String json1 = "{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘铭','age':16}]}";    // 数组    String json2 = "['北京','天津','杭州']";    //1、    //静态方法    Grade grade=JSON.parseObject(json1, Grade.class);    System.out.println(grade);    //2、    List<String> list=JSON.parseArray(json2, String.class);    System.out.println(list);  }  //生成  @Test  public void test2(){    ArrayList<Student> list=new ArrayList<>();    for(int i=1;i<3;i++){      list.add(new Student(101+i, "码子", 20+i));    }    Grade grade=new Grade(100001,"张三", list);    String json=JSON.toJSONString(grade);    System.out.println(json);  }}

public class JackSonTest {  //解析  @Test  public void test1() throws Exception{    // 对象嵌套数组嵌套对象    String json1 = "{/"id/":1,/"name/":/"JAVAEE-1703/",/"stus/":[{/"id/":101,/"name/":/"刘一/",/"age/":16}]}";    // 数组    String json2 = "[/"北京/",/"天津/",/"杭州/"]";    //1、    ObjectMapper mapper=new ObjectMapper();    Grade grade=mapper.readValue(json1, Grade.class);    System.out.println(grade);    //2、    ArrayList<String> list=mapper.readValue(json2,         new TypeReference<ArrayList<String>>() {    });    System.out.println(list);  }  //生成  @Test  public void test2() throws JsonProcessingException{    ArrayList<Student> list=new ArrayList<>();    for(int i=1;i<3;i++){      list.add(new Student(101+i, "码子", 20+i));    }    Grade grade=new Grade(100001,"张三", list);    ObjectMapper mapper=new ObjectMapper();    //将对象转换为JSON格式字符串    String json=mapper.writeValueAsString(grade);    System.out.println(json);  }}