当需要处理超大JSON文本时，需要Stream API，在fastjson-1.1.32版本中开始提供Stream API。
实例对象：
public class VO {
private int id;
private Map<String, Object> attributes = new HashMap<String, Object>();
public VO(int id) {
super();
this.id = id;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Map<String, Object> getAttributes() {
return attributes;
}
@Override
public String toString() {
return "VO [id=" + id + ", attributes=" + attributes + "]";
}
}
序列化
超大JSON对象的序列化
如果你的JSON格式是一个巨大的JSONObject，有很多Key/Value对，则先调用startObject，然后挨个写入Key和Value，然后调用endObject。
public class TestHugeObjectSerialize {
public static void main(String[] args) throws IOException {
JSONWriter writer = new JSONWriter(new FileWriter("hugeObject.json"));
writer.startObject();
for (int i = 0; i < 10; ++i) {
writer.writeKey("x" + i);
writer.writeValue(new VO(i));
}
writer.endObject();
writer.close();
}
}
文件内容：
{"x0":{"attributes":{},"id":0},"x1":{"attributes":{},"id":1},"x2":{"attributes":{},"id":2},"x3":{"attributes":{},"id":3},"x4":{"attributes":{},"id":4},"x5":{"attributes":{},"id":5},"x6":{"attributes":{},"id":6},"x7":{"attributes":{},"id":7},"x8":{"attributes":{},"id":8},"x9":{"attributes":{},"id":9}}
超大JSON数组序列化
如果你的JSON格式是一个巨大的JSON数组，有很多元素，则先调用startArray，然后挨个写入对象，然后调用endArray。
public class TestHugeArraySerialize {
public static void main(String[] args) throws IOException {
JSONWriter writer = new JSONWriter(new FileWriter("hugeArray.json"));
writer.startArray();
for (int i = 0; i < 10; ++i) {
writer.writeValue(new VO(i));
}
writer.endArray();
writer.close();
}
}
文件内容：
[{"attributes":{},"id":0},{"attributes":{},"id":1},{"attributes":{},"id":2},{"attributes":{},"id":3},{"attributes":{},"id":4},{"attributes":{},"id":5},{"attributes":{},"id":6},{"attributes":{},"id":7},{"attributes":{},"id":8},{"attributes":{},"id":9}]
反序列化
超大JSON对象反序列化
public class TestHugeObjectDeserialize {
public static void main(String[] args) throws IOException {
// 读入上面输出的文件
JSONReader reader = new JSONReader(new FileReader("hugeObject.json"));
reader.startObject();
while (reader.hasNext()) {
String key = reader.readString();
VO vo = reader.readObject(VO.class);
System.out.println(key + "：" + vo);
}
reader.endObject();
reader.close();
}
}
输出结果：
x0：VO [id=0, attributes={}]
x1：VO [id=1, attributes={}]
x2：VO [id=2, attributes={}]
x3：VO [id=3, attributes={}]
x4：VO [id=4, attributes={}]
x5：VO [id=5, attributes={}]
x6：VO [id=6, attributes={}]
x7：VO [id=7, attributes={}]
x8：VO [id=8, attributes={}]
x9：VO [id=9, attributes={}]
超大JSON数组反序列化
public class TestHugeArrayDeserialize {
public static void main(String[] args) throws IOException {
// 读入上面输出的文件
JSONReader reader = new JSONReader(new FileReader("hugeArray.json"));
reader.startArray();
while (reader.hasNext()) {
VO vo = reader.readObject(VO.class);
System.out.println(vo);
}
reader.endArray();
reader.close();
}
}
输出结果：
VO [id=0, attributes={}]
VO [id=1, attributes={}]
VO [id=2, attributes={}]
VO [id=3, attributes={}]
VO [id=4, attributes={}]
VO [id=5, attributes={}]
VO [id=6, attributes={}]
VO [id=7, attributes={}]
VO [id=8, attributes={}]
VO [id=9, attributes={}]
