java - 将深度嵌套的 json 转换为 java 对象，反之亦然

Question

我正在使用 JAXB 将 json 转换为 java 对象。我面临的问题是，它导致我创建了大量的类，这些类除了充当 json 标签的占位符之外没有其他任何用途。

例如:考虑下面的 json:

{
"proposalAggregation": {
    "Buys": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "Sells": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "TAChanges": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "Existing": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "Proposed": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    },
    "PIAChanges": {
        "Heading1": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        },
        "Heading2": {
            "key1": "value1",
            "key2": "value2",
            "key3": "value3"
        }
    }
}

}

现在要将此 JSON 按原样反序列化为 java 对象，这些是我需要创建的 java 类:

Class ProposalAggregation --> this contains Buys, sells, existing, porposed,TAChanges, PIA

Class Buys extends Calculation
Class Sells extends Calculation
Class Existing extends Calculation
Class proposed extends Calculation
Class TAChanges extends Calculation
Class PIAChanges extends Calculation 
Class Calculation -- > this contains heading1 and heading2

class Heading1
Class Heading2

总共有 9 个类来模仿上面的 JSON，如果我们看看这些类的作用，它们只不过是 JSON 标签的占位符。 有什么简单的方法吗？

Answer 1

您可以通过以下方式实现 Google 的 GSON 库。已经展示了一个示例类，您可以进一步修改它。

类 - ProposalAggregation

package com.test;

import java.util.Map;

public class ProposalAggregation {

private Map<String, Map<String, String>> Buys;
private Map<String, Map<String, String>> Sells;
private Map<String, Map<String, String>> TAChanges;

public Map<String, Map<String, String>> getBuys() {
    return Buys;
}

public void setBuys(Map<String, Map<String, String>> buys) {
    Buys = buys;
}

public Map<String, Map<String, String>> getSells() {
    return Sells;
}

public void setSells(Map<String, Map<String, String>> sells) {
    Sells = sells;
}

public Map<String, Map<String, String>> getTAChanges() {
    return TAChanges;
}

public void setTAChanges(Map<String, Map<String, String>> tAChanges) {
    TAChanges = tAChanges;
}

public String toString() {
    return "BUYS=" + this.Buys + " \nSELLS=" + this.Sells + " \nTACHANGES="
            + this.TAChanges;
}

}

测试主类 请注意，我修改了 key 名称只是为了验证转换是否正确。

package com.test;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

import com.google.gson.Gson;

public class TestClass {

    public static void main(String[] args) {
        Gson gson = new Gson();

        try {

            String jsonString = " { 'Buys': { 'bHeading1': { 'bkey1': 'value1', 'bkey2': 'value2', 'bkey3': 'value3' }, 'bbHeading2': { 'bbkey1': 'value1', 'bbkey2': 'value2', 'bbkey3': 'value3' } }, "
                    + "'Sells': { 'sHeading1': { 'skey1': 'value1', 'skey2': 'value2', 'skey3': 'value3' }, 'ssHeading2': { 'sskey1': 'value1', 'sskey2': 'value2', 'sskey3': 'value3' } }, "
                    + "'TAChanges': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } }, 'Existing': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } }, 'Proposed': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } }, 'PIAChanges': { 'Heading1': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' }, 'Heading2': { 'key1': 'value1', 'key2': 'value2', 'key3': 'value3' } } }";


            // convert to java class
            ProposalAggregation obj = gson.fromJson(jsonString, ProposalAggregation.class);
            System.out.println("OBJECT : " + obj);

            // convert to json
            String jsonStringFromObj = gson.toJson(obj);
            System.out.println("JSON : " + jsonStringFromObj);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

这是输出。

OBJECT : BUYS={bHeading1={bkey1=value1, bkey2=value2, bkey3=value3}, bbHeading2={bbkey1=value1, bbkey2=value2, bbkey3=value3}} 
SELLS={sHeading1={skey1=value1, skey2=value2, skey3=value3}, ssHeading2={sskey1=value1, sskey2=value2, sskey3=value3}} 
TACHANGES={Heading1={key1=value1, key2=value2, key3=value3}, Heading2={key1=value1, key2=value2, key3=value3}}
JSON : {"Buys":{"bHeading1":{"bkey1":"value1","bkey2":"value2","bkey3":"value3"},"bbHeading2":{"bbkey1":"value1","bbkey2":"value2","bbkey3":"value3"}},"Sells":{"sHeading1":{"skey1":"value1","skey2":"value2","skey3":"value3"},"ssHeading2":{"sskey1":"value1","sskey2":"value2","sskey3":"value3"}},"TAChanges":{"Heading1":{"key1":"value1","key2":"value2","key3":"value3"},"Heading2":{"key1":"value1","key2":"value2","key3":"value3"}}}