Jackson

Posted 2020-09-28 Mr.yang.localhost

 

1》包含两个对象

        String testRootStr = "{\\"tUser\\":{\\"mId\\":1,\\"mName\\":\\"test model\\",\\"mDesc\\":\\"model1 desc\\"},\\"tClass\\":{\\"dId\\":1,\\"dName\\":\\"test Demo1\\",\\"dDesc\\":\\"demo1 desc\\"}}";

TestRoot testRoot1 = mapper.readValue(testRootStr, TestRoot.class);
        TestRoot testRoot2 = mapper.readValue(testRootStr.getBytes(), TestRoot.class);

　　　　 Map map1 = mapper.readValue(testRootStr, Map.class);

 2》包一个对象 和 一个List集合

        String testRootStr = "{\\"tUser\\":{\\"mId\\":1,\\"mName\\":\\"test model\\",\\"mDesc\\":\\"model1 desc\\"},\\"tClass\\":[{\\"dId\\":1,\\"dName\\":\\"test Demo1\\",\\"dDesc\\":\\"demo1 desc\\"},{\\"dId\\":2,\\"dName\\":\\"test Demo2\\",\\"dDesc\\":\\"demo2 desc\\"},{\\"dId\\":3,\\"dName\\":\\"test Demo3\\",\\"dDesc\\":\\"demo3 desc\\"}]}";

TestRoot testRoot1 = mapper.readValue(testRootStr, TestRoot.class);
        TestRoot testRoot2 = mapper.readValue(testRootStr.getBytes(), TestRoot.class);

　　　　 Map map1 = mapper.readValue(testRootStr, Map.class);

 3》一个对象 和 一个List集合，List的对象内部有一个List集合

        TestRoot testRoot = new TestRoot(){{
            settClass(new ArrayList<TClass>(){{
                add(new TClass(){{
                    setdId(1);setdName("test Demo1");setdDesc("demo1 desc");
                    setStudentList(new ArrayList<Student>(){{
                        add(new Student(){{setStuId(1);setStuName("张三");setStuMsg("张三是个好学生");}});
                        add(new Student(){{setStuId(2);setStuName("李四");setStuMsg("李四是个好学生");}});
                        add(new Student(){{setStuId(3);setStuName("王五");setStuMsg("王五是个好学生");}});
                    }});
                }});
                add(new TClass(){{setdId(2);setdName("test Demo2");setdDesc("demo2 desc");
                    setStudentList(new ArrayList<Student>(){{
                        add(new Student(){{setStuId(3);setStuName("张三");setStuMsg("张三是个好学生");}});
                        add(new Student(){{setStuId(4);setStuName("李四");setStuMsg("李四是个好学生");}});
                        add(new Student(){{setStuId(5);setStuName("王五");setStuMsg("王五是个好学生");}});
                    }});
                }});
            }});
            settUser(new TUser(){{setmId(1);setmName("test model");setmDesc("model1 desc");}});
        }};
        String testRootStr = mapper.writeValueAsString(testRoot);

反序列化：

        String testRootStr = "{\\"tUser\\":{\\"mId\\":1,\\"mName\\":\\"test model\\",\\"mDesc\\":\\"model1 desc\\"},\\"tClass\\":[{\\"dId\\":1,\\"dName\\":\\"test Demo1\\",\\"dDesc\\":\\"demo1 desc\\",\\"studentList\\":[{\\"stuId\\":1,\\"stuName\\":\\"张三\\",\\"stuMsg\\":\\"张三是个好学生\\"},{\\"stuId\\":2,\\"stuName\\":\\"李四\\",\\"stuMsg\\":\\"李四是个好学生\\"},{\\"stuId\\":3,\\"stuName\\":\\"王五\\",\\"stuMsg\\":\\"王五是个好学生\\"}]},{\\"dId\\":2,\\"dName\\":\\"test Demo2\\",\\"dDesc\\":\\"demo2 desc\\",\\"studentList\\":[{\\"stuId\\":3,\\"stuName\\":\\"张三\\",\\"stuMsg\\":\\"张三是个好学生\\"},{\\"stuId\\":4,\\"stuName\\":\\"李四\\",\\"stuMsg\\":\\"李四是个好学生\\"},{\\"stuId\\":5,\\"stuName\\":\\"王五\\",\\"stuMsg\\":\\"王五是个好学生\\"}]}]}";
        TestRoot testRoot1 = mapper.readValue(testRootStr, TestRoot.class);
//        Map map1 = mapper.readValue(testRootStr, Map.class);
        TestRoot testRoot2 = mapper.readValue(testRootStr.getBytes(), TestRoot.class);
        Map map = mapper.readValue(testRootStr,Map.class);

4》包含两个对象，一个对象内有属性 + List集合

{"tUser":{"mId":1,"mName":"test model","mDesc":"model1 desc"},"tClass":{"dId":1,"dName":"test Demo1","dDesc":"demo1 desc","studentList":[{"stuId":1,"stuName":"张三","stuMsg":"张三是个好学生"},{"stuId":2,"stuName":"李四","stuMsg":"李四是个好学生"},{"stuId":3,"stuName":"王五","stuMsg":"王五是个好学生"}]}}

 5》list集合反序列化

String string = "[{\\"stuId\\":1,\\"stuName\\":\\"张三\\",\\"stuMsg\\":\\"张三是个好学生\\"},{\\"stuId\\":2,\\"stuName\\":\\"李四\\",\\"stuMsg\\":\\"李四是个好学生\\"},{\\"stuId\\":3,\\"stuName\\":\\"王五\\",\\"stuMsg\\":\\"王五是个好学生\\"}]";

//反序列化
List<Demo> demoList = objectMapper.readValue(string, new TypeReference<List<Demo>>(){});

转换问题

反序列化时，json含有的字段，对象不含有，会报错，添加一下配置解决：

    public static final ObjectMapper objectMapper;

    static {
        objectMapper = new ObjectMapper();
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }