[Android环境下，JSONB解析报错，com.alibaba.fastjson2.JSONException: set address error, offset 17]

[Fish-Bin]

问题描述

JSONB.parseObject(bytes, Student.class)报错

环境信息

请填写以下信息：

• OS信息： [e.g.：CentOS 8.4.2105 4Core 3.10GHz 16 GB]
• JDK信息： [1.8]
• 版本信息：[implementation 'com.alibaba.fastjson2:fastjson2:2.0.12.android']

重现步骤

如何操作可以重现该问题：

1. 使用 JSONB.parseObject(bytes, Student.class) 方法
2. 输入 Student student = new Student("bin",12,"湖北"); byte[] bytes = JSONB.toBytes(student); Student student2 = JSONB.parseObject(bytes, Student.class); L.INSTANCE.i("Bin", student2.toString()); 数据
3. 出现 com.alibaba.fastjson2.JSONException: set address error, offset 17 错误

       Student student = new Student("bin",12,"湖北");
        byte[] bytes = JSONB.toBytes(student);
        Student student2 = JSONB.parseObject(bytes, Student.class);
        L.INSTANCE.i("Bin", student2.toString());

public class Student {
    private String name;
    private int sge;
    private String address;

    public Student(String name, int sge, String address) {
        this.name = name;
        this.sge = sge;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getSge() {
        return sge;
    }

    public void setSge(int sge) {
        this.sge = sge;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", sge=" + sge +
                ", address='" + address + '\'' +
                '}';
    }

期待的正确结果

对您期望发生的结果进行清晰简洁的描述。

相关日志输出

com.alibaba.fastjson2.JSONException: set address error, offset 17
at com.alibaba.fastjson2.reader.FieldReaderStringMethod.readFieldValue(FieldReaderStringMethod.java:34)
at com.alibaba.fastjson2.reader.ObjectReader3.readJSONBObject(ObjectReader3.java:176)
at com.alibaba.fastjson2.JSONB.parseObject(JSONB.java:328)
at com.bin.jsonb.TestActivity.test1(TestActivity.java:45)
at com.bin.jsonb.TestActivity.access$000(TestActivity.java:16)
at com.bin.jsonb.TestActivity$1.onClick(TestActivity.java:25)
at android.view.View.performClick(View.java:7317)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:967)
at android.view.View.performClickInternal(View.java:7291)
at android.view.View.access$3600(View.java:838)
at android.view.View$PerformClick.run(View.java:28247)
at android.os.Handler.handleCallback(Handler.java:900)
at android.os.Handler.dispatchMessage(Handler.java:103)

附加信息

很好的一个库，最近想用它来优化项目存储，但是感觉对安卓支持力度很小，JSONB的一些基本功能都不能正常跑通

[wenshao]

是因为Student类没有缺省构造函数，你可以用FieldBased模式试试看，比如：

Student student = new Student("bin",12,"湖北");
byte[] bytes = JSONB.toBytes(student, JSONWriter.Feature.FieldBased);
Student student2 = JSONB.parseObject(bytes, Student.class, JSONReader.Feature.FieldBased);

Android无法像服务器端那样，是因为在服务器端，是会把Class文件读取出来做分析，识别构造函数中的参数名，调用了一次非缺省的构造函数。Android上做不到，所以就功能对不齐了。

[Fish-Bin]

加上无参构造方法，或者加上JSONWriter.Feature.FieldBased确实可以，但是将Student对象转成kotlin就还是会报错

[Fish-Bin]

这个是kotlin对象

[wenshao]

https://oss.sonatype.org/content/repositories/snapshots/com/alibaba/fastjson2/fastjson2/2.0.13.android-SNAPSHOT/
问题已经修复，请用2.0.13.android-SNAPSHOT帮忙验证，FieldBased启用和关闭场景都已经支持。

需要在gradle中配置依赖：

implementation 'org.jetbrains.kotlin:kotlin-reflect:1.7.10'

[Fish-Bin]

1. 不引入implementation 'org.jetbrains.kotlin:kotlin-reflect:1.7.10'会报
   
2. 引入implementation 'org.jetbrains.kotlin:kotlin-reflect:1.7.10'的话编译会报：
   
   是我kotlin版本低了吗？我当前版本是 ext.kotlin_version = "1.4.32"，已经是比较新的了

[wenshao]

引入implementation 'org.jetbrains.kotlin:kotlin-reflect:1.4.32'试试看

[Fish-Bin]

1. 引入implementation 'org.jetbrains.kotlin:kotlin-reflect:1.4.32'可以了
2. @JSONField(name = "n") 会导致 JSONB.parseObject(bytes, JNote::class.java) 报错

3. @JSONField( serialize= false) 也会导致 JSONB.parseObject(bytes, JNote::class.java) 报错
   

对象信息：

[Fish-Bin]

类似的还有@JSONField(serializeFeatures = [JSONWriter.Feature.NotWriteDefaultValue])
@JSONField(format = "yyyy-MM-dd HH:mm:ss")
@JSONField(serializeUsing = TypeSerializer::class)
@jsontype(ignores = ["noteId","firstPageId"])
@jsontype(serializeFeatures = [JSONWriter.Feature.NotWriteDefaultValue])
这些注解不生效的问题,麻烦排查下

[wenshao]

@Fish-Bin 发文本，按照图再输入一遍很烦人

[Fish-Bin]

data class Note(
var noteId: String = "",

var name: String? = "",
var firstPageID: String = "",

var type: Int = 1,

var maxPageNumber: Int = 9999,

var deleteFlag: Int = 0,

var userid: String = "",

var backgroundUrl: String = ""

var paperParamConfig: String = "",

var lastPageIndex: Int = 0,

var parentId: String = "",

var isImpOutline: Int = 0,

var paperWidth: Float = 1024f,

var paperHeight: Float = 1750f,

var modify: Boolean = false,
var needDown: Boolean = false,
var isClouding: Boolean = false,
var cloudId: String = "",
var progress: Int = 0,
var maxProgress: Int = 0,
var fileSize: Int = 0,
var firstBackgroundUrl: String = "",
var scaleGlobal: String = "",

)

[Fish-Bin]

    val note = Note(
        noteId = noteId,
        name = "无名",
        firstPageID = pageId,
        type = 1,
        maxPageNumber = 9999,
        userid = "77800484",
        backgroundUrl = "PageBg/White_Wide_Line_Paper",
        parentId = "",
        firstBackgroundUrl = "/Cover/natural2",
        paperParamConfig = "{\"defaultHorParts\":5.0,\"defaultVerParts\":5.0,\"horParts\":0.0,\"paperBg\":\"PageBg/White_Wide_Line_Paper\",\"verParts\":0.0}",
        lastPageIndex = 1,
        isImpOutline = 1,
        paperWidth = 1240f,
        paperHeight = 1750f,
        scaleGlobal = "bin"
    )

[wenshao]

主要是data class不允许为空，使用Feature.FieldBased就好了

[Fish-Bin]

主要是data class不允许为空，使用Feature.FieldBased就好了

好的，我验证下

[Fish-Bin]

在对象头上也要加上@jsontype(serializeFeatures = [JSONWriter.Feature.FieldBased])这个吧，不然也还是报错

[Fish-Bin]

加了Feature.FieldBased 后 @jsontype的大部分注解都生效了，除了JSONWriter.Feature.NotWriteDefaultValue不生效，但是会导致@JSONField的注解都不生效了

[wenshao]

https://github.com/alibaba/fastjson2/releases/tag/2.0.13
2.0.13版本已经发布，请用帮忙用新版本验证